Umm because as it sits, Canonical is looking to use Mir on the desktop by April of next year. A bold statement I think they intend on fulfilling. Every big Linux player will keep eye out as Canonical pushes this "ALPHA STAGE CRAP" (as you call it) forward and tries to change the landscape of desktop Linux
Canonical still hasn't opened up the XMir code at lp:~rocket-scientists/xserver/xmir :(
And an experemental Weston port was running on droids last year
And here's some estimated costs of Weston alone, not taking account the actual design and development of the protocol and collaboration with toolkit developers and Mesa developers:
Obviously the proof will be in the pudding. As some Wayland programmers have said , they believe Canonical's projects are messy.