to me it seems more like the pile stuff on top of each other, trying to make bad stuff below the surface go away after it's sufficiently plastered over. but it

to me it seems more like the pile stuff on top of each other, trying to make bad stuff below the surface go away after it's sufficiently plastered over. but it never is 100% complete and you can still find components even from the Win3.x era. it's just that some releases they have plastered it a bit more completely (7) and others where it's most superficial (8, 11); Vista is a special one as it brought a major new kernel version, which afaik they are still using to this day.