That's an assumption that needs to be verified. Sure, over a generation it's quite unlikely that evolution made for better mouse users.

But we don't need to go that far. I mean, when you were testing during the development of the Mac, it was what, 1983? The mouse was a new thing, CUA didn't exist yet, I doubt that many vim and emacs users were part of the target group.

I doubt that speed changes if you test the same demographic as back then, although it's harder to find people as unaccustomed to mice.

In addition, has there ever been a test that includes mouse chords as used in Acme/Oberon?

I think speed could change over time because our generation uses computer and common shortcuts from childhood. People who participated in the study could have been much less experienced users at that time and the shortcuts might have been less established and more varying from platform to platform