I am not convinced Paul had much to do with it. Fact is, the congregations Paul wrote to seemed to be very well established. Paul just kept them informed and in line. It was arguably John the Baptist that set up the infrastructure of the religious order that Jesus appropriated. In point of fact, it is contentious as to who died first, Jesus or John the Baptist. History is written by the winning side, and Jesus just happened to be on the winning side. It could just as easily have been ‘Baptistianity’.