Look at Craigslist. The UX sucks and they haven't done anything with it in a while. But people use Craigslist, with no one able to displace it at scale, simply because it has gravity and users don't go elsewhere. Niches is the best way to unentrench a social network, but these are just as saturated as vps hosts and aren't likely to get investor attention. I would cut your losses and find lower hanging fruit.
