All I really want from a social network is to be able to share small files with my friends and see small files that my friends have shared with me. It's convenient to have a for-profit handle all the hard parts (checking whether people are who say they are, storing the stuff when one of us is offline, etc) but it's not an actual requirement. Especially if some portion of the members of the network have a $5 VPS, which is certain to be true.
(As an aside, it mystifies me that some VPS provider hasn't already built this. A FOSS decentralized social network that requires a small dedicated server would be like a whalefall for that industry. If I were a PM at Amazon, I would have a team contributing 'store my files on AWS instead of my phone' to Scuttlebutt right now, and ditto for every other promising-looking decentralized social app.)