1) OSX doesn't change significantly. People ranted about OSX for years, until one day they kinda stopped. Because OSX was new and fresh, right up until the point when it became the same thing that it's been for 13 years.
2) More people use Windows so more people are talking about Windows.
3) Therefore, OSX is better because [insert reason].
EDIT: Incidentally, the Windows 8 UI overhaul was terrible. Really terrible. I mean, that does need to be pointed out. Apple got a lot of stick for some slight changes to the way their icons appear on the newer version of the iPhone (forgive me, I'm not an Apple user so I can't comment, I just know the word 'skeumorphism' was thrown around with various levels of anger), but Microsoft seemed to get a much quieter and meeker acceptance of their terrible UI overhual. Yes, there were articles at the time saying "what is Microsoft thinking?", but it seemed -- at least to me -- to just be wearily accepted that Microsoft had dramatically changed their UI so that it was unusable for anyone coming from a previous version of their OS.
I'm not really sure why there wasn't more consumer outrage about Windows 8. Every Windows 8 user I speak to hates its UI, but they just seem to hate it and get on with it. Maybe it's because Windows users are generally less excited by their OS than Mac users? I've never really known a Windows user to speak at any great length, positively or negatively, about their OS.
To be honest, I actually like it. Not enough to use Windows over Linux, but the Metro UI is really cool. Has search functionality, and every app is essentially its own self-updating widget. Very cool.
It's still useless pagination.
The hardware finally started to be fast enough for it to not be a slideshow. Early releases of OS X were so resource-hungry, and OS 9 ran like a rocketship on the same hardware. Besides, the G3 and early G4 Macs weren't really that fast anyway.