<<So, if GTK+ 3 flopped, how are we where we are today, with GTK+ 3 suddenly being forced down our throats? It turns out it was probably started by Red Hat.>>
Systemd, gnome 3, I think that it is Red hat that ruined the desktop experience in the last decade by imposing terrible choices on everyone else...
As for systemd... while I believe that there have been questionable decisions (why was a replacement of ntpd needed?), at least it's gotten easier to introduce dependencies as part of software startups - e.g. it's relatively trivial to add a dependency on an NFS mount for a server program, which was ... a complex mess to put it lightly before.
My biggest gripe with systemd unit files is that there are at least four ways of specifying dependencies (Wants, BindsTo, After, Requires) and the semantics are not easily understandable.
Systemd, gnome 3, I think that it is Red hat that ruined the desktop experience in the last decade by imposing terrible choices on everyone else...