Except for necessary modern features like different fractional scaling on multiple monitors...

Haven't you heard? In 2025 software isn't ALLOWED to be complete. If you're not constantly playing a cat and mouse game with someone's pet ideological crusade in your dependencies, you're an irrelevant dinosaur and can't possibly be a critical or functional part of anybody's workflow.

X11 is "complete" in the sense that we have followed it to the end of the road. X11 has a series of well documented fundamental problems that does not make it suitable for a modern OS. I will not belabor them here (except to note that security in particulat in X11, is exceptionally weak for modern standars). These issues are unfixable because they are built into core assumptions and behaviours of all legacy apps.

At some point there has to be a switch. There simply is not manpower to maintain 2 separate windowing systems. I am sure we would all want there to be an army of devs working on these things on maintain the 2 stacks. But that is not the timeline we live in. The number of devs working on these things is very low.

Was it too early? I don't know. There will never be 1-1 feature parity with 30 years of legacy apps. I honestly believe that fixing things like a11y are gonna be much more tenable with only a single windowing system.