NFL football is the only other sport I still have some interest in, but I think it's because it's a short season, once a week, and the playoffs fit neatly into the MLS offseason.
Pretty much sums it up for me too. I do consider myself a Rangers (NY) fan but I only really bother to watch the playoffs at this point. Don't know how anyone has the time to regularly watch NHL, NBA or MLB regular season.
You both hit my fandom right on the head. I love my Isles, nets and yanks. But can't be bothered to watch all those games (84, 82, 162!). It's way too much. Maybe they catch me if they are on a west coast swing and I need something to fall asleep to. Otherwise it's just the playoffs. Soccer and football on the other hand are once a week and have alternating seasonal schedules and limited number of games. Summer = soccer (34) & winter = football (16). So, I follow those two things. It's worked out quite nicely.
Also, best part about being a Jets fan; I don't have to worry about extra playoff games to tune into!