Linux development is mostly funded by corporations working on the server side. The desktop is an afterthought, and it very much shows. They haven’t even managed to fully expunge X yet. NeXT showed people how to put a proper UI on top of Unix in 1989!

I would say that Sun with NeWS did as well.

UNIX was developed as an headless OS for timesharing terminals, and to this day it shows that doing proper UIs as never been a strong UNIX culture, which Steve Jobs famously didn't had in high regard.