What happened?
I'm guessing that people got fed up with churn and started to realise that change for its own sake is annoying. Getting irritated at having to get used to a new system AGAIN that does things worse in many cases is not unreasonable. Being fed up with churn is not the same as fearing change.
Personally, I like to see "change" actually make things better, because if it doesn't then why bother with the change? And if it makes things worse, then WTF?
A lot is just uninspiring and meh. Going from flat to bevelled to bulbousd and back to flat (hello Athena!) user interface elements is just a huge meh. I mean sure, now they're coloured and antialiased and with nice fonts and whetever, but I really can't feel myself getting excited about "flat" design. Actually, personally I think it's a bit of a usability regression becase it's harder to explain to people which the active user interface elements are.
Change where it's an improvement I like. I like large, high res screens. I like running a modern kernel with all the new power saving features and better, newer filesystems and so on and so forth. I tend to run recentl builds of tools I like like vim and mplayer because the changes make them better than the old version. I keep promising myself I'll finally switch from Xterm to Terminology, but I can't get some of the features to work properly at the moment.
All those things, all those changes have made stuff better. On the other hand, I still run FVWM2. I've tried more modern things, but they all seem to make things worse in interesting ways. I've still adopted some changes, however which make it more modern.
I think there are quite a few people here with similar opinions to me. Another example: the reason that tablet stuff coming to laptops is bad is because a lot of the UI stuff is designed around single, non cooperating, full screen apps. I don't want that, not because I fear change, it's because I changed AWAY from it in the 90s and I have no desire to go back to the bad old days. I remember what it was like all too well (and my phone just keeps on reminding me). What I fear is being dragged back to something I know from experience is inferior.