But they probably will break things that aren't broken.
There are people who have managed, however they had to do it, to get input systems working in current versions of Gnome.
Everyone suspects because of past history with these things, that these new improved versions of Gnome will break all the currently working things. And, these new "improved" versions of Gnome will have no way to turn off the new things because the Gnome developers want to force everyone else to fix the problems rather than revert to what already works.
The distros don't help with this because they make it nearly impossible to run older versions of desktop software. For example, if you want to use a new version of Ubuntu, all of the packaged software will be linked to the newest possible version of Gnome. The same with Fedora.
For many people then, to keep using software that works and still get at least some modern features, like hardware support for this year's laptops, they will have to switch to using Gentoo Linux or more likely Mac OS X.
So in the quest to make things "better" Gnome developers often end up making it impossible to get work done and drive people to proprietary software.