What you say is true, but I think you have the chronology backwards. There were proprietary network and information protocols before open ones. The open came after the closed. Same with operating systems - linux and the BSDs came after. There are already some stabs at open social media (like Diaspora, although I'm not sure if that project's still viable). The point is, proprietary systems are often the vanguard, because money is good incentive, and when you've got financial backing, you can blaze trails faster. Open protocols usually follow the trails blazed by their commercial predecessors. There's no reason to imagine that, given time, open social protocols will not evolve and come to dominate.