Another as yet unmentioned factor: video games.
When I was a kid, to enjoy the joy of sports, you played. Everything in its season, football, basketball, and baseball. Our TV showed four channels, NBC, ABC, CBS, and whatever channel 5 was (Fox nowadays). There was no alternative. All the kids around simply played the games. Some were better, some not so good, but almost everyone played in some fashion or another.
The Play Station and X Box games are incredibly detailed and theses kids can have a lot of fun with sports via the video games. Heck, high school, college,and pro players play the heck out of these games too.
At some level, a kid that may not feel he can compete on a real field can have a lot of fun on the couch.
At every level, when players leave a game, what they inevitably miss most is the interaction with teammates-the bus trips, the locker rooms, the wise cracks. Most game results fade from memory, but the "stories" live on. Video games will never replace that, but the kids have no idea what they're missing.