On point 2: in my experience, the tradeoff is that baseball is the most accessible in-person major league sport. The quantity, length, and seasonal timing of games means that tickets are almost always affordable and can fit into my schedule. I go to more and more MLB games every year, whereas a ticket to my NFL team is a serious expenditure, and that's assuming that my schedule works out to where I can attend one of 8 home games for the entire year.

The NFL and MLB seem to have similar numbers of recent dynasties and of different teams that have won a championship.