XP also shipped with the 2000 skin and it was trivially easy to switch over.

It was easy to switch but there is a lot to be said for sane defaults. With each new iteration of Windows I'd find more and more insane defaults (for me at least). It started with file extensions being hidden by default. Then system files too. By the time XP was released I was finding that I had to spend an hour just configuring the system how I liked...and that was before I installed any software.

Users will sometimes reach a point where they say "If I'm having to spend this much time configuring new installs to function how I like, then I might as well install something else that already ships with the defaults I like". And this is why many power users started drifting away from Windows in the decade of 2000 to 2010.

Windows Server having file extensions turned off by default still drives me crazy. I get it for the desktop versions, but it would be fantastic if server editions had it on, or it saved and picked up the toggle from your AD account/profile.

I agree generally about the importance of sane defaults, but the theme was just soooo damn easy to switch, and a lot of non-techy people I know did so.

I actually don’t really associate Windows XP with its theme in my memory, because I so rarely saw it in use.

Yep. Even switched it over when you went to the lower resources usage settings.

I have to stick up for XP because i have so many fond memories from my young adulthood of using it. I never had a problem with it's default theme but it also shipped with a few other themes that were better. like olive and then later the zune theme which was arguably the best one.

People said that (as well as Skittles OS) since it launched.