Motor oil and oil filter cost.

I am just the opposite. Why spend a few bucks more for something that has no proven benefit?

Does the $29/jug of Mobil 1 EP oil do anything more than the $21.50 jug of Supertech Advanced Synthetic oil in the timeframe/mileage being used? Both are 20,000 mile oils (which almost no one will use for that mileage).
Same for the filter. Is there really a difference in using a basic Supertech filter for $3.50 vs a Fram Synthetic Endurance For $13?

You could go the "expensive" route and spend $42, or the "cheap" route and spend $25, and would bet have the exact same engine life.
$820 in 100,000 miles vs $500 in 100,000 miles if you change the oil every 5,000 miles (probably the median of most here).
Sure it is only $320 more over that mileage, but what did you gain for that $320?
"Peace of mind"?
OK, good for you.

Me personally, I still have a stash of ~$0.50 qt synthetic oil of various weights and manufacturers.
Once that is gone, I will buy the cheapest API rated oil and a Fram orange can or Supertech filter and drive my vehicles, not worrying about the engine life based on what oil I use.

Changing the oil and filter on a regular basis (based on several factors) has more to do with engine life than what oil and filter you use or how much it cost.
Completely agree.

My approach is to do the best maintenance at the cheapest possible price, which for me consists of short OCI's with a low priced full synthetic oil and low priced high efficiency oil filter. The oil is not left in the engine long enough to cause varnish/sludge/gummed up oil control rings/piston rings, and will never come out of the oil drain hole during an oil change as dirty/sludgy/clumpy.
I haven’t had to shop for oil in over 3 years. I buy oil on sale to save money (a nickel saved is a nickel earned) and because it’s convenient.