Plenty of evolution can happen. The problem with Wayland to me is that it's not evolution, but a step backward. It's forcing a tremendous amount of boilerplate and duplication of code.

X can evolve both by extensions and by "pseudo extensions" that effectively tell the server it's okay to make breaking changes to the protocol. There are also plenty of changes you could just make and accept the breakage because the clients it's break are limited.

I don't mind breaking changes if they actually bring me benefits I care about, but to me Wayland is all downside and no upsides that matter to me.