Isn't it rather like Microsoft used to be, when they can assume that their sweeping changes will be unquestioningly accepted by everybody, no matter what the final result is like? I thought open source freed us from that. Of course, I'm grumpy that Kubuntu moved to KDE4 by default. I know KDE3 is still available, but c'mon, how could the Kubuntu guys look at KDE3 and KDE4 and decide to ship KDE4 as the default? When I installed Lucid (to give KDE4 yet another try) notifications were sized and stacked illegibly, and I kept losing notifications I didn't want to dismiss. Do a fresh install with default settings, and basically the first movement you see on the screen reveals a major usability problem! Well, it's obvious how that happens -- months before the final product is even scheduled to be finished, distros have already decided when to unleash it on their users.
Fedora is typically very liberal distribution when it comes to package versions and they usually try to ship the latest reasonably stable version of every package with each release. People who choose Fedora (like me) accept that or even like that. The reason Red Hat sponsors Fedora is because it acts as a test bed for future Red Hat Enterprise Linux releases.
If you need a more conservative distribution, you can try RHEL or Debian, or Ubuntu which is a bit more conservative than Fedora but a lot less conservative than, say, Debian. Linux distributions are about choice, really.
It's not a matter of distro priorities being conservative vs. cutting edge. It's about distros ignoring their priorities and marching ahead with whatever the GNOME and KDE projects say should be next. Ubuntu is supposed to be about usability, which isn't served by taking a big jump down in polish and completeness. Fedora is supposed to be up-to-date, but it isn't supposed to install incomplete or buggy software by default. Who knows what GNOME3 will be like in October? Not Fedora. They have no way of knowing whether GNOME3 will be in an acceptable state.
Let's face it; distros jumped to KDE4 because they want it to be great someday and they're delivering users to support that dream. GNOME3 looks like more of the same. They're supposed to be delivering software to users, not the other way around.
"Isn't it rather like Microsoft used to be, when they can
assume that their sweeping changes will be unquestioningly
accepted by everybody, no matter what the final result is
like? I thought open source freed us from that."
The other reply to your post says this, but doesn't frame it this way: open source does free you from that. You can move to any number of functionally-equivalent distros that made different decisions (from superficial things like GNOME vs KDE, or more fundamental things like how aggressive or conservative they are). Or install your own window manager. These are totally supported use cases.