I think that what you are calling "KDE" may be "Plasma", since you are comparing with another desktop environment.
To answer your question, yes, and the process started some years ago. It sounds like you may be a bit out of the loop, as Plasma now weighs more or less the same as XFCE, or thereabouts (these things are harder to measure than one may assume). I personally installed Plasma 6 on a Dell XPS PP25L from 2008 and it works flawlessly.