Decentralized vs. Federated https://lemmy.ml/post/2416512
Well such ownership tends to be based on communal recognition anyway. The community sort of chooses its own owner through members of the community agreeing that so and so is the owner.
If the creator or current owner disappears, it would be up to the community to first recognize that and secondly react to it, probably by coming to a general agreement that someone or someones else will be the new owner.