This all supposes that the sports team owners really are that: independent owners. Sure that’s what we call them, but it’s more accurate to say they are equity partners in a common enterprise.

It’s not interesting to say that a sports league controls whether there is a new team. Of course it does, just as an existing supermarket chain decides where to open new stores, or an airline decides what cities to fly to. Competition for a sports league comes from other leagues (not necessarily in the same sport) or from different forms of entertainment entirely.