Internet-delivered content is an augmentation technology, not a replacement technology.
It's important to frame the key reasons why IPTV is gaining traction:
1) Time shifting (watch what I want, when I want it)
2) Place shifting (same as #1, but not primary viewing location)
3) Archived content (watch past episodes / missed recordings)
4) Niche content (Limited distribution, ie: Revision3)
Tme shifting is by far the largest driver towards Internet-based delivery, and it also represents the most inefficient use of network resources. You're taking content that is already being digitally delivered to your house via OTA ATSC feeds, cable QAM feeds, and satellite QPSK/8PSK feeds.... and transferring yet another copy of the same content over the network. Time shifting is better accomplished through local capture and playback using an already established stream as the source.
In terms of IPTV making things cheaper, just look at ESPN. Disney currently gets approximately $3.65/mo in subscriber fees from 100.7 million viewers thanks to forced channel subscription packages that won't let viewers opt-out of channels. Is anyone really naive enough to believe that ESPN is going to make a move that threatens their $4.4 billion a year money train? IPTV isn't going to change the game in terms of channel pricing because it's the companies that produce the content who want things packaged the way they are. It's not a coincidence that the channel line-up of cable and satellite providers everywhere in the US have a high degree of consistency across their channel lineups in various packages.
Internet-based video has a huge future, but not as a replacement technology.