Sports fans have been using live P2P streaming for many years, the most obvious being Sopcast (sopcast.org - even the website is copyright 2007). The quality is pretty good, and the 'danger' posed was made clear with some of the first domain seizures being the stream aggregators - myp2p, rojadirecta etc.
The difficulty with this technology 'replacing TV' is that realtime is only truly relevant for a few things - sports, maybe concerts and awards ceremonies - beyond these the on-demand paradigm is much more attractive.
That's not to say that at scale a certain amount of bandwidth offloading couldn't happen to equivalent-timecode peers, but I suspect the biggest challenges to the complete overthrow of the cable networks model right now involve the notorious impossibility of negotiating agreements with the content owners, not the bandwidth/hardware cost of server-client streaming.
The difficulty with this technology 'replacing TV' is that realtime is only truly relevant for a few things - sports, maybe concerts and awards ceremonies - beyond these the on-demand paradigm is much more attractive.
That's not to say that at scale a certain amount of bandwidth offloading couldn't happen to equivalent-timecode peers, but I suspect the biggest challenges to the complete overthrow of the cable networks model right now involve the notorious impossibility of negotiating agreements with the content owners, not the bandwidth/hardware cost of server-client streaming.