The NBA and MLB season are just so long there are long stretches where the games aren't all that interesting. In MMA every fight means something for every fighter involved. I really don't think it's comparable. Every NBA teams plays 82 games and the teams that make it to the Finals play plenty more then that. There are something like like 160 MLB games for each team. Where as a fighter will only fight 1-4 times a year, I don't know the average for fights per year for just guys in the UFC but I would guess it's about 2 per year.