The NBA performs OK locally. They perform great in really small markets where they're the main attraction, but with the exception of LA - admittedly a big exception - they're not a patch on baseball in larger markets.
Only three NBA teams averaged more than 6 locally, 7 MLB teams did. In the larger markets:
- The Sox drew twice as many per night as the Celtics
- The Knicks barely beat the Mets, and drew about 40% less than the Yankees. Hardly anybody watches the Nets (I don't have their numbers handy but I recall them being really low).
- The White Sox and Cubs, despite being awful, draw about the same as the Bulls do every night.
- The A's and Giants draw 2x what the Warriors draw.
- The Phils get 100K a night, God only knows what the Sixers get. The Flyers get 56K a night...I can't imagine the Sixers getting close to that.
LA is the one exception, the Lakers still do really well though nobody watches the Clippers.
But that strength in other large markets really helps MLB, despite having to play more night games than the NBA, playing twice as many games, playing in the summer when there's more things to do, etc.