I think it might be somewhat generational. There was a time when Apple famously put a lot of effort into HCI research and experimentation, and prioritized it above so many other concerns. When Apple chose to do UI differently from everyone else, it was a strong indication that they made the decision based on empirical research and not just making it up as they go along like everyone else. A single menu bar at the top of the screen, for example, was chosen because they found that users could locate and click on them much faster than they could menus at the top of the window. I can’t remember exactly how much but I think it was something like 1/3 - 1/2 as much time.

But that was in a different millennium.

IIRC Bill Atkinson said that it is at the top because it was easier to code. at any rate, it’s true that screen edges and corners are easy to click because their hit region becomes infinite in one or two directions