The ability to use whatever theme you want has created a situation where Linux UI is in complete disarray. If you want a different UI you should obviously have

The ability to use whatever theme you want has created a situation where Linux UI is in complete disarray. If you want a different UI you should obviously have that option, but there isn't a major UI system that takes the opposite approach, instead developer effort is being wasted on a feature that's always broken all the time and restricted to handful of working themes anyway.