By observation, not only did many of the domestic auto manufactuers hurt themselves in not really paying attention to the imports' products, but many didn't know how to gauge what they were seeing or what it would lead to in later years. In the middle 1970s, I went out to look at new cars as a "cheap entertainment" situation. I started to notice that Pontiac Grand Prix seats were not contoured as you might expect them to be on the upper part of the front bucket seat seat back--they were ALL crooked and angled from horizontal. These were the same years of Grand Prixs that had the "thin" vinyl roof material that was gone in a few years. But the drive trains were pretty bulletproof and generally had no problems, other than a possible timing chain issue at about 80K miles.
By observation, almost EVERY engine family in EVERY manufacturer's vehicle will have some cyclical issues. My '77 305 never had any unusual engine noises, but in '78 the change to lighter-weight cylinder heads did result in valve jobs needing to be done by 35K miles. There were also some Chevy 4.3L V-6s in the earlier Astro vans that had oil sludge issues at about 80K miles or so, yet no problems in other vehicles it was used in. The middle 1980s Toyota minivans, the ones with the engine between the front seats, the engine would cook itself in extended-idle (think a flower shop delivering flowers to a hospital in July in TX) situations. All of these problems lasted for a few years on certain models and then we didn't see those things any more.
By observation, we generally don't see the whole vehicle segment and the problems that each one might have from time to time. For example, we heard how sorry a particular Chevrolet/GM diesel engine was (due to the starter becoming loose and then shearing starter bolts or breaking the block in that mounting pad area), but when I got around people who owned Ford 6.9L diesels, they had the same problems--just that the disgruntled Ford owners didn't talk to the disgruntled Chevy owners. Basically, both owners were in the same boat and didn't know it, on that particular issue. And there were others too, then and now.
I concur that domestic manufacturers are producing much better products now--even if some of them might appear to be incredible flimsy compared to prior designs. The reason I'd not have any qualms about a 500K+ mile domestic engine is due to the general beefiness of the lower end of the short block. This would include bearing surface areas and widths, for example, which I suspect would be more generous than many similar import engines (just a hunch).
A situation which "bit" Mercedes a while back was their oil change interval (generally a Euro length) vs the type of oil which USA buyers were putting in the cars (generally the least expensive dino oil). Seems that European owners are supposedly more prone to use synthetic oil and go for a longer OCI, but when USA owners used the same OCI with less expensive oils, things cratered and Mercedes generally paid the bill. It also became apparent to me that one reason that BMW went to a "full maintenance" warranty was to make sure that only specified oils were used in their vehicles . . . and then turned that into a selling point for their vehicles, which saved them money in the long run and the issues which Mercedes had to endure. I recall seeing some threads in here about which BMW engines took which particular viscosity of oil so they would live as long as they should.
I suspect that in the 1970s, the Detroit operatives looked at a Toyota Corolla and though "WE do better than that". More size, more comfort, more style, etc., which was probably true, but when the economy advantage of the imports became important, it WAS important to the purchasers of them. As for fuel economy, the old Mobil Economy Run was for domestics only and demonstrated what ultimate fuel economy could be achieved with OUR vehicles. Some of the favorites might have been a little shaken if there had been some imports in the mix, I suspect, but in the total mix of things, Ford and GM and Chrysler all had viable economy cars back then, which would generally hold up as long as if not longer than many of the imports would. One high school friend had a couple of paper routes stacked together. He drove Plymouth Valiant Slant Sixes exclusively. Engines never had any problems, but the rear axles did (for some reason). I don't recall any such stellar recommendations from similar Ford or GM owners, though, of cars in that size class.
Yet some of the things that were important to import buyers were not the same things as for domestic vehicle buyers, it seemed. Only thing was that when buyers branched out to purchase an import, it was a basic bare bones sort of vehicle rather than a high-style domestic-type vehicle. It was obvious that these people didn't feel the need to trade every year or so, so when the cosmetics went away, all they cared about was reliability and such. To some, it was "kool" to drive an import. And those loyal buyers returned to buy another import when that one was finally not worth fixing, which began a pattern that Detroit did not address, although they certainly knew what brand loyalty was (thinking they had a handle on that). The imports responded with some typically American responses of nicer vehicles and expanded model ranges. Hyundai, KIA, Toyota, Nissan, etc. have ALL followed the former General Motors orientation of "A vehicle for every purse and purpose", but many critics have not realized that, even now. What Toyota does is great, what GM does is less so--no matter what, for example.
In the middle 1980s, Toyota had a "Cheap to Keep" advertising campaign. One day, I was at a larger Toyota dealership and picked up one of their factory-recommended maintenance schedules, with appropriate pricing on the chart. It was a pretty good maintenance list. For the first two years or so, there were lots of "check" items with "No Charge" by them, but by the third year, there were many things that had started to creep in which did cost money to get done. MANY of these things were things that a similar domestic would not have needed (by observation and experience), like changing the rear axle fluid at 36K miles (when the domestic vehicles did not even recommend that, unless it was a P-Trac or similar). So, it became apparent that the least expensive vehicle to own and maintain over the very long run was something like a Chevy Caprice with a 305 V-8 (rear wheel drive, rugged and reliable engine--all known technology that anybody could generally work on and maintain pretty easy, which was also highly durable). They certainly didn't have any $80.00 choke pull-offs as some of the imports and domestic 4-cyls did. So . . . what you generally saved on fuel with an import should have been put in a savings fund for when it might break and cost to get it fixed or for general maintenance, as you drove around in a smaller car with less space to carry people or "stuff" in. In reality, the costs would have been pretty much equal, I suspect.
I know that some people rag on a particular engine for various reasons and these things get spread around the Internet community as gospel. Everybody has their own experiences and observations on these things, which is understandable and I respect that, but I also feel that by and large, USA designed engines are just as durable as any import brand engine--especially with the same level of required maintenance which is seemingly necessary to keep an import engine alive (and also affect ultimate resale value when "the books" are requested by a potential owner). And that situation is not something that just materialized, but something that's been here for at least 40 years. If you bought a domestic brand car, you were expected to get a newer one in a few years to prove your affluence and related prosperity, yet it was fine to buy a VW beetle and keep it forever, for example. Same if you bought a used Corolla and used it to commute to work, age and miles did not mean you were doing something wrong with keeping that car. An American car would have done the same things, if kept an extended period of time, too, but nobody was really oriented to do so.
Detroit seems to have a somewhat bad habit of not doing something until they are under the gun to do so (possibly a "financial" orientation to maximize shareholder returns??), whereas the earlier imports all tended to have highe levels of build quality, even for an inexpensive vehicle whose paint would fade and die within a few years. Comparatively, the oriental imports were doing something they didn't have to do, but did it anyway.
The Chrylser people proved that for the same money you can do something mediocre, you can do something neat. Look at the difference in the Chrysler K-cars and the LH cars that replaced them. Both cars had their place in Chrysler's history, but it was the LH cars and their different designs that put the golden eggs in the Chrysler bank accounts back then. Not to forget about the Ram truck's new designs that are still influencing what Ford and GM do. Or the current Chrysler 300.
I know there can be some compelling reasons to buy import brand vehicles (even ones assembled in the USA), but my orientation is still toward the "home team" (including the Chrysler Group) for having the generally most durable vehicles on the planet that will live with minimal maintenance and care and still look pretty decent in the end. I feel sure that any of them have a decent chance of making 500K+ miles with no serious engine problems, with at least factory-recommended service intervals (even using the GM Oil Life System to gauge OCIs). Of course, all of this is somewhat dependent upon use and user as some could wreck an anvil in a sand pile and not know what they had done as they did it. Not everybody desires to keep a vehicle past when the payment book is empty, or a year past that, and how they take care of the vehicle can reflect that orientation.
Enjoy!
CBODY67