I agree. Anecdotally, I also see more PCs with maximized windows in the wild, and more Macs with smaller windows. (I don't really see many people using Linux in the wild.)
I'm curious if you're seeing this on desktops? My sample of mac users is very heavily biased towards laptops (and I've only used macos on a laptop) - but I've seen the exact opposite.
(And I'll note that in my own usage, when I'm on my 11" Macbook Air I full screen most apps. But that's a weird edge case due to the screen size.)