It's not. Wayland has really gotten its shit together in the last 5-ish years. A lot of the desktop ecosystem has matured in the last few years, actually.
I maintain that the Linux desktop in 2021 was actually less usable than it was in 2016. But things have really turned around since then.
I'm not particularly fond of X11 but barely working in 2026 is hardly an endorsement of the whole project.
A good replacement of X11 would have had a well designed local mode that abstracted modern hardware in all configurations and an actually good network protocol.
We're left with a barely-working local mode with awful X11 stuck on top.
And we've moved to it for purely political reasons.