Linux

For many uses, Wayland has feature parity now or is even the superior option. That is how it can be the default on so many systems ( including RHEL9 as per the article ).

Compositors that do not provide the features that uses want will fail to compete ( what you mean by become useless I assume ).

That said, different users will want different things and, unlike X, Wayland allows competing compositors to address different communities. Some compositors will lack features some users want while offering features that other users need. A composite targeting embedded use cases may not need multi-monitor or fractional scaling features for example. A security focussed option may think that global hot-keys and external lock-screens are anti-features. I think the Wayland world could be quite interesting.

X11 is also just a protocol, and will live on with or without Xorg.

Right so I guess I should have over specified that I hope ALL the other bits that actually make it function the same will also catch up and for example something as basic as forwarding GUI programs will simply work without jumping through a bunch of tedious flaming hoops with pitfalls on either side. It doesn't really matter to me that Wayland has decided it's somebody else problem.