KDE(5) is indeed dead.
I'm still happily running KDE 3.5.10. I know it contains security vulnerabilities but I have JS completely disabled in KDE settings and I never use Konqueror to browse the web.
Every time when I try KDE 5 I face so many visual glitches and inconsistencies along with a few dozen of bugs, I give up right away. Besides I cannot understand why KDE 5 needs two versions of KDE and QT libraries. I mean I understand that some KDE components haven't been upgraded to KDE 5 frameworks or whatever their name is, but KDE 5 is ... TWO freaking years old.
And let me tell you this: plasma sucks big time. It's a crashing monstrosity with monstrous memory and disk requirements. For some reasons some KDE devs thought KDE would be useful as a platform for tablets but I don't know a single person on this planet who runs KDE on their tablets. So, now we have this semi-usable crashing shit instead of something lean and fast.
On my new PCs I happily use more or less dead XFCE (not actually dead but dormant) for the simple fact that it's still maintained and included in distros. Of course there's Trinity but speaking frankly I don't trust it. I'm not in a position to audit their code (I'm not a C++ programmer) and some of their design decisions are simply horrible - e.g. they renamed most QT/KDE classes and added their own prefixes without any reasons whatsoever. It's not like KDE3.5/QT3 are still developed and there could be any conflict.
I guess the real reason for the renaming was that TDE's core developer was afraid someone would start stealing his code to patch ages old KDE 3.5.10. The net result is that a dozen of people in the world use TDE and most distros shun it. Had they continued patching KDE3.5/QT3 to make them usable again on modern Linux distros, distros would have included them right away.