The month of February is the dark period of sports. When the Super Bowl ends, there is nothing really compelling to watch or talk about until the NCAA Tournament (unless you are a NASCAR fan - see Daytona). The NBA, NHL, and College Basketball are fun to watch during this time but there is nothing that forces me to follow them. While I'll watch a game to pass time, I don't adjust my schedule to watch the games or even make it a point to spend 3 hours on ESPN.com to check stats. I don't think "Oh boy, another regular season game!" but instead think "I guess the Virgina Tech vs. Wake Forest game is better than watching that Walker Texas Ranger rerun."
While Baseball's regular season is long, it keeps people's interest during the summer since there is a game everyday and your favorite team will play at least 6 days out of that week. It is always top of mind. The NFL and College Football have regular seasons where every game matters. Even though each team only plays once a week, the excitement builds during the week leading up the games. I guess NASCAR is popular for this same reason. The only variable is the time the games are played.
On the other hand, the other leagues have no set day for teams to play on. Schedules are set at the discretion of T.V. contracts. NBA teams can play back-to-back nights while taking three days off in a row. A NHL team can have three games one week and one the next. It is hard to keep the excitement level high when for your team doesn't play on a consistent schedule or is top of mind. I guess I can put a team's schedule in my outlook but it is not the same as a routine of some type. Besides, I'm to lazy to do that.
That's why the playoffs are nice for all of them. Teams (at least in the NHL) play two games, get a day off, and then play two more. That is at least bankable and excitement can build. It doesn't hurt that the games means something but consistency helps remind people the games matter.
I wish this was a winter Olympics year (since they usually take place in February) but I guess I will spend my extra time this next month reading a John Feinstein book.