MLB is partially to blame for this issue. When it's all Yankee-Red Sox, all the time regardless of whether or not you give a damn, it has an impact.
When those teams don't get to the series a vast amount of the baseball fan base is rather ho-hum, who cares...."who are these Giants? Never heard of half the guys playing for Cincinnati" and so forth.
MLB needs to start promoting and representing all teams, even garbage ones like Kansas City and Houston. If Fox doesn't like it (or ESPN) MLB needs to explain who is running the show. I understand the networks have a say in things given the money they are spending but you can't fall on your knees every single time they ask for something.
Bob Grim has told me about the things the Sox have to do at times for ESPN when they televise a game and I've got to tell you, it's a wonder Bob and his people don't tell them to go **** themselves.