From where I'm standing it looks like Canonical wants to create a real Windows/OSX competitor by doing things separate from rest of the community and emulating Apple and MS.
By now I think Ubuntu will _not_ get Gnome-shell as a default. More likely is a pimped up version of their Unity shell. I think Mark read "Differentiate Or Die" a few times too many(often?). By now he wants Ubuntu to be the platform for for-pay cloud/music/app/digital services/goods and be its own separate thing.
Problem is that Google has the exact same idea with Android and ChromeOS, but with much less for-pay stuff and enormous industry support.
I still think RH has the best and most sustainable FOSS business model so far, hell, I might even switch back to Fedora if their update madness can be tamed (e.g. not include brand new stuff like SystemD etc.)