re: Is 0w20 really what is best for our vehicles?

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But the fact is the lighter oils ARE worse for wear.

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Blanket statements like this are rarely correct.

A lighter oil may or may not allow more wear in an engine. Even if a higher viscosity oil has a higher film strength the engine still has to be designed to use it. Thicker oils than recommended will run hotter and will not coat tight tolerance parts as well and will be slower, especially at colder temperatures at getting oil to all the internals on cold starts. Oil pumps designed for thinner oils can have issues keeping the volume high enough at the far ends of the oiling system.

There is zero doubt that in the search for CAFE benefits and HP numbers from manufacturers that don't care about CAFE for certain vehicles, we are seeing thinner oils. But jumping up several oil viscosities on an engine designed with lower viscosities in mind will likely increase wear vs decreasing wear.

There are reasons to go outside the manufacturers suggestions for oil but if thicker is better in a blanket way then why not run 90 weight gear oil in your crankcase?