It isn't an alternative to Facebook unless my grandma can use it, and she couldn't set this up for herself. The idea that centralized storage is the problem masks the actual concern. There is nothing inherently wrong with centrally stored data. There is a problem is when it is locked down by a 3rd party, and/or you don't control how it is used.
Arguably it isn't FB if regular college kids can't use it. If they can subsequently onboard less tech savvy people, so be it, but that could be a future goal.