"Unseating X" is not what Wayland will do, at least not anytime soon. Even X's developers realize that X's architecture has gone a little stale given the current desktop use cases, so they are working to make X a Wayland client. X is likely not going to go away for another 10+ years at least, provided every X app ever developed gets converted into a native Wayland app... And that's a LONG time off on the horizon.
Wayland NAILED it where every attempt to replace X outright prior to it, failed miserably. Wayland is the future only because it allows X programs to run -unmodified-, while at the same time providing a new, more performant window server.
Wayland is the bridge to the future, along with X.