I don't think you're wrong. It was the EPA who started reducing the amount of zinc and other anti wear additives because of something to do with Catalytic Converters on cars. Or so I have heard
Sometimes, we 'improve' things to the point that they no longer function.
Boeing took an airplane that's been in service since 1967 and improved it to the point that it can longer leave the ground. It now has the longest duration grounding of any commercial airliner.
As a kid, we had to pay close attention to AA, AAA, C, and D cell powered devices because the batteries would leak and ruin them. Then, that problem virtually disappeared. Leaking batteries were a thing of the past. Until now. They leak again.
Hope the same thing isn't going to happen with oil!
I agree with everyone. EPA mandates to have any auto get a certain MPG & be so clean, by a certain year, so the car makers are doing everything they can to try & comply..
And of course the thinner the oil, the more it would cost. Kinda like low profile tires.. Less sidewall = more $$$
