Wayland is being treated like PulseAudio and systemd before. So, it will probably win its battle, thanks $DEITY.
That's because all three are similar, all three throw away some of the modular unix philosophy and replace it with a system that gives less power to the user.
If you think that the window manager was modular component you can basically pretend that wlroots is X and the compositor is the window manager. It is just as modular with that logic except more efficient and capable.