I think you've got it backwards. It's true that TiVo didn't include a 30 second skip as a concession to the broadcasters. But it's Replay that always had the potential and now does show advertisments on the screen (when paused). The original story was that Replay's basic guide was "free" (not really) and in the future they might choose to show adverts on it but would offer an enhanced guide that cost money and had no adverts. TiVo has always charged an additional fee for their service and I've never heard about any possibility of them showing forced adverts. They do have areas in their UI where broadcasters can buy space but you never have to visit these areas if you don't choose to.

I'm sorry, but I don't think the networks are such bad guys here. How else do you propose they make money?

-Dylan