actually, Joe Wieder and Arnold would take top spots and if you wanted to split hairs just think what came first, the chicken or the egg.
as a business from the start, joe weider own(ed)(s) bodybuilding after he got involved with the sport. So it's as if after joe weider got into bodybuilding he wound up owning it and after Arnold got into to it he wound up becoming it.
Arnold would have become a success with or without bb'n and joe would have owned bb'n anyway.... but having each other when they did allowed them swifter successes.