My theory is that it's all about convenience and network effects. So if a fully decentralized IPFS based/alike social network would come out with mobile apps and was marketed as the way to communicate, it could have success. The big fault such projects make is to stress the technical merits and forget to play the psych-advertising game.
I've seen non-technical people have the most number of messenger apps on their phones, and some even advocated the security of their favorite messenger. Technical folks seem to be harder to persuade to join a messenger network to communicate with a new person in their life.
So I want to say once we will have a couple more high profile data breaches and centralized SPOF downtimes, people will care about security and availability, though history doesn't support they would.