This would rapidly become the Unix-wars of the 80's all over again... OR Microsoft would gladly step into Google shoes, completely uninvited but unchallenged, while wielding their deadly patent swords.
I think it would resemble Linux personally, each vendor would probably set up their own app store and their own package system but binary compatibility would probably remain. There is just too much at stake for all involved to fracture it as bad as the Unix wars.