If I understand Wayland correctly, this isn't something that's built into the kernel. If so, then that means that, even when Wayland becomes the default display manager, we can do a commandline install and install X.org instead of Wayland.
In that case, will X.org always be available in the repositories in case someone needs the core features of X.org?
Best Answer
First of all, before we jump the gun here, X.org is not going anywhere just yet.
For situations where wayland is not supported, X will remain the fallback. Plus, X will still be maintained and available.
That covered, wayland will provide many of the features X does, can run a nested X server, etc.
Sorry for not including links, I might do that if I update my answer later.