Yeah, from the perspective of starting something cooperatively funded from scratch, I think it's basically about "what would it cost to get something running and keep it worth using," balanced against "what would people actually be willing to pay?"

In my dreams, if the price point were low enough, like "the cost of two coffees per year" or something, and it wasn't irritating to pay it, there are plenty of people who want out of FB and could afford that.