As cool as it is, the reality is that geography changes: cities evolve, roads are built, closed, etc. Maintaining an up-to-date database of those views can only be done to serve another, very lucrative purpose, the one of which only Google & al. can offer. I don't think a community-based approach can work when the scale of effort is this high.
This is really interesting, but I'll second the intuition that building a critical mass for StreetView-like data is probably one of the hardest thing to crowdsource.<p>It's just not fun to be driving each and every road around where you live. Besides, without an hemispheric camera data is really limited.