It's not shame...

There are supporters who aren't partners. Those are sometimes more likely to contribute back. Some partners mainly care about getting the code to work on their devices and some to make proprietary forks. Users care a lot, just look at the cyanogen mods.

> And this "competitive advantage" is... what exactly? I know of only one: "given enough eyeballs, all bugs are shallow".

You are joking right? Are you deliberately ignoring everything you have learned here on LWN? How about features, alternative platform fixes, general maintenance, refactoring cleanups, documentation, artwork, design ideas, ...

> And it does not work for short-lived forks.

Honeycomb is likely only a short lived fork in the sense that it is likely to merge back with the non honeycomb tree. It is hardly a throw away fork. Add helping to complete and merge honeycomb to the list of things that contributors could do.

I don't think that google would create and host an open source code review contribution tool (https://review.source.android.com) just for android if they didn't think that outside contributors could be and advantage.