I tend to agree. I like being able to install whatever distro I want and add the DE of my choice, and there is a glut of different combos to choose from.
However, are KDE and Gnome going to gradually focus on making their respective DEs work on their own branded OS, rather than any old base system? I know that's a worst case scenario, but putting a lot of added effort into a full OS is a nontrivial investment for a desktop environment. Some mission drift might be expected.
I think immutability gaining steam made this a good time for this, normally i'm against distros for the sake of distros, but the kde one is going to be an immutable arch based distro and i think we really needed a good kde immutable arch based distro, and I think it'll be great for the masses too!
don't know anything about the gnome one, probably will also be good.