It feels like they don't have UX designers planning the workflows (or even involved). And that's largely because they don't, right? They have developers building some stuff and doing it however they want, and not really following any sort of enforced brand or style guidelines.

Mostly the various Linux distros still feel like "model train sets" -- built by one guy, for one guy to enjoy alone in his basement. It's work to build something as part of a larger team... designers, developers... then you'd need a manager... and probably some sales people to keep it all funded... easier to just avoid all that stuff and build a model train set. (=

Most of the distros don't take kindly to UX people or product people giving suggestions on GitHub, or other places. It's very much a "if you aren't a dev, we don't want your input" type situation. "You don't get to tell us what to build, not here, not outside of work..." and until Linux makes a real effort to include a variety of people (especially designers!) in the build process, the results will always be the same.