KDE was founded in 1996. That means that in 2020 it'll be 24 years old.
Twenty. Four. Years.
Gosh! That's almost as long as Windows!
And it has given its users the same basic UI paradigm -- windows, titlebars, buttons, panel, start menu from 1997 onwards. That desktop will still be around in eight years.
I'll grant you your "interruptions" -- for people eager enough to always install the latest version, instead of going with the supported 3.x versions while 4.x was settling down, but then, living through Windows 95, ME, XP, NT, 2000, Vista, 7 (and 8) hasn't been the bed of roses. Not for users, not for developers.