Excellent points John. Part of the issue is whether dino or syn the oil you buy is a package. Most riders buy oil based primarily on viscosity, cost and propaganda. Some even look at the API rating but don't know what it means. One of the big things is how long the oil actually maintains those numbers on the bottle. I used to think a 0W50 HAD TO BE better than a 10W40. Not so. When a oil is produced, it starts with base stock and then comes the additives. To get that 0W50 extenders are added to the base stock at birth, but run it for a 1000 miles and you might have 10W30 in the crank as the chains of molecules break down. Synthetics are "supposed to" not break down as fast as dino's. Maybe, but like you say John, how good does it really need to be. IMO, I go back to an old saying from my youth, "don't sweat the small do do."The folks that make Synthetic oil quack about how great it is, but never really indicate what's so good about it. Why is it better than it organic brother? We do know that it is supposed less susceptible to heat, we know that it has a higher surface tension, but what else?
Now the question is just how good does it really need to be?
So, IMHO the reality is that super high performance motor oil in our bikes may be overkill. Something that is "good quality" most likely will never let us down, providing it's the right grade and weight and is changed on a regular basis.