The issue is that X was never a mature, feature-complete, stable project.
Looool. It was too stable, which means stagnation.
bloated hodgepodge of disparate and barely working patches.
You mean bloated protocol or bloated implementation? Because kwin_wayland is pretty bloated.
The entire point of Wayland is to do exactly what you say tech should do: solve the particular problem (graphics server) well and cleanly, and limit itself to a definable set of features so it can actually reach that point of stability.
Tying graphics server to audio server is very clean.