They are in fact not. FIFA is not the only football games, PES exist too with fully licensed leagues. Some of them shared between both. MLB has right now two

They are in fact not. FIFA is not the only football games, PES exist too with fully licensed leagues. Some of them shared between both. MLB has right now two licensed games (RBI and The Show) NBA, NHL, and NFL had multiple games between 2K (2K Sports) and EA. It really comes down to who is willing to pay the enormous fee.