I think you mistake the protocol for the implementation. Catholicism is extremely consistent at a protocol level. I can go to almost any Catholic church in the entire world and experience the same Mass, even at the Vatican. That is the protocol. The implementation is the church, the people and priests there, how they operate, how they act, what decisions they make for their community, how they build trust, etc. Every church is funded by its community; no church gets money from the Vatican to operate. In this way each individual church lives or dies by its community. In this way it is as decentralized as it gets.

The Vatican rarely messes with the Mass and when it tries to there is global pushback. Resurgence in the Latin Mass has come from a grassroots interest, for example, not from the top down.