Congressional respresentatives can easily have more than 10,000 'contacts.' It would be interesting to see if Microsoft's Exchange server can handle more than 10,000. Active Directory certainly can. So perhaps it would be a competitive feature.

For this community however I would agree there is always a tension between the 80 - 90% solution and the outliers. If you have more business than you can handle, supporting outliers seems like a waste of resources, the problem comes when someone decides to support those outliers and builds a system that can handle your customer base as well. That gives them the high ground competitively.

From Google's perspective I suspect its not like they get enough revenue from this whole Apps business to make it worth their while, it seems to be more of a way to poke MS than a product. (But disclaimer time I use Google's app)