The magazines, newspapers, TV news stations, etc. are reporting on the meet after the fact. And even then they are paying a fee for some of the aspects of those reports. Think those photos in the newspaper are free? Think the clips on the nightly news or Sportscenter are free? Nope, all cost money. Some stations will send their cameras to the meet, but the use of those images are tightly controlled by the restrictions of the press credentials. For example, KCRA (the local Sacto station) can't produce and sell a DVD of the NCAA track meet, but they are allowed to show a few clips of the "local boy doing well" in the triple jump.
Think about it this way: the NCAA charges for admission to the national track meet, as it does with nearly every other regular season and championship competition in every sport. The NCAA wants to protect this revenue stream (around 15000 people @ $xx a head...I don't know the exact numbers but you can do the math). If someone with a camera is broadcasting the meet from the stands and broadcasting live on the internet, the reduces the incentive of attending the meet. For a major sport like baseball or football, you're going to have enough of a fan base to fill the stadium and have plenty of people watching at home. However, track and field isn't as popular (really?).
However, the NCAA wants more exposure than the few thousand in the stands. But it also wants to be able to cover the expenses of the meet and deflect any possible loss in gate revenue. So broadcasting rights are sold to the highest bidder. The networks then have contracts with the NCAA to show these meets/games. They pay the NCAA to film the meet and for the rights to any video. Advertisers then pay the networks for ad space during the broadcasts. And we then pay advertisers. And around and around we go.
As the Internet grows, we're going to start seeing some changes in the way this is done. The archive of the Pre Meet is great, and I think it's something we're going to see more of.