[marssaxman]

ALTSpace in Seattle is still breaking even after twelve years, with no such endowments or grants. As you say, the membership has completely cycled through several times since the start, and there was a major spinoff several years in where several members pulled out to form their own, more private workspace. You have to expect all that and plan for it; you'll need a new generation of leadership every few years, and recruiting new members needs to be an ongoing process.