Why? There is proof to the contrary. The Eurovision Song Contest has been streamed via a decentralized peer-to-peer protocol (albeit proprietary) for some years now.
And the BBC is involved with that. So what is different here?
Furthermore, if they were to lose the ridiculous DRM requirements for programs (programmes?) which are already paid for, they could even use the actual Bittorrent protocol itself.
BitTorrent isn't.