Netflix is basically just an incremental update to the cable TV model: one centralized distribution service that negotiates broadcasting rights. The only real difference is that people are free to choose when to watch things, and even that is just an "Internet version" of the same thing people had with their VCRs (time shifting) or rental services. It is innovation, yes, but in a box that does not really change the larger business model; by way of analogy it is like railroads switching from steam engines to diesel locomotives.
Peer-to-peer is a totally different concept of global distribution, one that challenges the entire business model that is built around copyright. If Netflix is a diesel locomotive, peer-to-peer is an automobile -- it is more than just a new way to do the same thing that we had done previously, it is an entirely new concept of how things can be done. That is why the RIAA and MPAA panicked. They understand how to negotiate with or sue a centralized distributor like Netflix or Megaupload, but their entire business model is threatened by peer-to-peer distribution.
Bittorent is only half the promise of peer-to-peer. Yes, you are participating in distribution, but you still need a central service to help you find the torrents you want to download. Hardly anybody is working on distributed search, or good ways to deal with spam/malware/etc. that do not involve a central service of some kind. There was a time when people were talking about peer-to-peer messaging systems, but the death of peer-to-peer left us all relying on more centralized approaches.
Ironically, the death of peer-to-peer contributed to the rise of tech giants, all of which follow the same centralized model that peer-to-peer challenged. I think it is entirely possible that a peer-to-peer social networking system could have hindered the rise of Facebook. Youtube might never have been created if peer-to-peer had flourished. We may not have even been having this conversation if the talent that went into Google and Facebook had instead been devoted to peer-to-peer.
It is impossible to know. The problem with deliberately killing a technology in its infancy is that it is hard to know how the technology might have developed or what it might do for society. It is certainly possible (I would say likely) that consumers would have benefited from the growth of peer-to-peer technology.