Brilliant technical solutions are solutions to problems that people have, not problems we want to solve. As soon as there will be a serious problem, which can be solved by decentralized or federated social service — it will be solved graciously, designs are in place already.
Decentralized technology is in fact trying to solve a serious problem, but sadly it is a problem that most people choose to ignore in favor of the incentives offered by Facebook and other monolithic centralized services.
However, Facebook et al. provide and maintain huge, single-point-of-entry, solely owned, walled gardens with hostile privacy policies and yet they successfully serve millions of users...
err... try billions of users