Yes, and yes to both questions. These manufacturers "recommend" these thin oils to cut down on rotational resistance of the engine. Thereby increasing their CAFE mileage stats. You as an individual driver will never see a difference mileage wise. But a fleet of millions of vehicles over years, will see a slight increase. Enough to up their CAFE ratings. All of which translate into $$$$ for the automaker. Not longevity for the engines their consumers are paying for.Do you think the 0W-20 is lacking protection? Is it just for mpg vs longevity?
Remember all the manufacturer cares about, is the engine lives with minimal issues until it passes through the warranty period. I can't think of a single engine that wouldn't be better served, lubrication wise, with 0W-30, than it would with 0W-20. The only exception would be in all but Arctic freezing conditions in the dead of Winter.
I used to believe the Chrysler 5.7 HEMI V-8 had to use 5W-20 because of it's VVT and MDS Systems. However now I am in serious doubt about that as well. Because I have researched it, and found there are in fact MANY people running these engines with 5W-30, as well as 0W-40 in them, without any ill effects, or codes being thrown by the ECM. I'm going to switch to 0W-40 in my 5.7 HEMI this Summer from the 5W-20 it has been getting.