A friend who worked at MS tells me that there's a huge amount of "if version" in their code. Apparently it's at the level where it's a big maintenance headache.
IIRC it was partially confirmed when some Windows 11 beta builds started causing issues with software thinking it was being executed on 1.1.x (whose identifier internally apparently is 11).
Maybe for a while. But when you add the maintenance burden to the code, it stays there, forever being felt. Over time, this degrades the product for everyone. And indeed, Windows can be unpleasant to use, not least of all because it feels like glued together legacy systems.
