I think the main reason is promos. First off, radio broadcasts suck since they spend a good 30% of the time presenting you the subway 3rd down of the game followed by a Meineke sack and a KMart punt. At the same time, TV broadcasters promote shows coming up on Fox/CBS, and that is why they pay so much money for the rights to the games. If it were to be done, the networks would demand that customers pay a huge fee for the right, to discourage widespread distribution and offset potential ad decreases. Yeah...like I said, there's a ton of reasons it won't happen. But I would so much rather hear Joniak than Sam Rosen or Joe Buck.