Wayland has been around for many many many many more years than Wayland has been good enough to use. I think that’s about it.

I think that’s mostly it. When Wayland was first released, it was barely in an alpha state, with many major use cases not being supported at all. Since Wayland is a deep system component, it requires apps to adjust to them, and in the beginning this hadn’t happened at all so far, so really nothing worked.

And this didn’t change over night. That easily took a decade, and still today some use cases still don’t work well (e.g. accessibility/screen reader compatibility).