Actually on his website Mark wrote the following comment:
It’s highly unlikely that the default Ubuntu install in a year will be on Wayland. It’s possible that there will be versions of Ubuntu that use it, or proof-of-concept images, by then. More importantly, we won’t make it the default until it really is widely supported and supportable, by folks using a wide variety of hardware providers. And as for network connectivity, there’s sufficient time between now and then for these problems to get solved.
So he doesn't intend to use it for the MAIN distro so soon but they start to work on it and therefore there will be a proof-of-concept.
However, I think that for a good home-PC experience it makes sense to move to something that doesn't use the Client/Server technology for GUI in the future (though when exactly is a different question). Is it because of "Unity"? They want to start using Unity for the normal Desktop-Environment in the future though (although they won't use it for everything from "day one").
From where do you get they idea that it is only for mobile devices because this is wrong.