I realize this and have read the threads here for years, even though I've only owned a hemi for a few months.
Does UTG completely miss that though? Haven't all domestic push-rod V8s with lifters have pressure lubed lifters both for the bore and lash adjustment bits on them like forever?
To me, he talks at length about how the lifters lay so flat that any oil running down the lifter body (be it pressure lubed or not) falls off before it reaches the roller and needle bearings for the rollers. That and how that oil gallery pipe blocks oil flinging off the crankshaft from reaching the cam and rollers. I can't bring myself to watch/listen to the video again. LOL and yes.. I get it that it's been talked about.
Yeah, he completely misses it, he says the lifter bores are splash lubed and that's why he was seeing varnish and that no oil was able to make its way to the rollers completely missing the fact that the lifter bores are constantly being fed a steady supply of oil from the pump, the excess, which is what goes down the body and onto the roller.
And yes, the lifters lay on a more severe angle than your typical vee engine but they definitely aren't flat.
This design is more dependant on lifter bore lubrication of the roller assembly than your traditional small block, which also had a splash lube component, but rollers are less reliant on a generous oil film in that area than FT engines, so I expect that was a design consideration. Given that most of these engines live long, healthy lives, I wouldn't conclude it's a design flaw of the engine but rather an issue with the lifters, hence the multiple revisions. That said, we can't rule out valve float as a contributor to that failure.
Engines that idle a lot will of course have lower oil flow and a higher propensity to accumulate varnish. I recall one of the failures on the truck 6.4L we saw, which was run on M1 0w-40, had a surprising amount of varnish and it was noted that the engine was in a wrecker and so the truck sat and idled constantly, waiting for calls.
Our lone fleet vehicle that experienced lifter failure was a truck that spent most of its time in town. Lots of stop and go, probably a fair bit of idling, so its service, on the same NAPA 5w-20 that the rest of the trucks see at the same interval would be more severe and I suspect it had a LOT more varnish inside than the other trucks, many of which are higher mileage, some significantly at well over 200,000 miles.