How important is open source to the Google Android?

Google's open handset alliance is based on open source, but is that a game-changing thing in the mobile market?

Here on ZDNet, there's a thread about how Android kicks open the mobile open source door, which may well be true. If nothing else, it finally looks like a mobile Linux alliance that could just succeed.

But I still need convincing that the open source community has actually evolved a model that works on mobile devices. Linux is diverse, and it has had enough trouble dislodging the monolithic alternative on the desktop, where there's plenty of screen all the user interface options you could want.

Phones are even more monolithic - big players like Symbian and Microsoft succeed, others don't. Can the Linux community produce something that monolithic? It would have to line up behind the Google brand, something pretty alien to Linux. Or can it succeed in the mobile business with a non-monolithic approach?