Re: Is this as ususal software related?
Win32 rewrite? When do you think that was?
I've seen the Win2000 shell code and compared the dissembler and callstack from Win7.
Mostly, the dissembler is what you expect from the Win2000 source. Key difference can be seen in the callstack, there is a load 'async helper' stuff (undocumented) at the top.
There is a few interfaces (not all documented....) but at least what I looked at was no rewrite. Just a turd polished harder.
Win7 was better on multicore than Vista because they made what they could asynchronous.
The WINE source for same stuff is wwwwaaaayyy cleaner.
Write between Win7 and Win10, I doubt it. Main different was building in spyware and 'modern' theming and desktop.