There is a bit of a flaw with this argument. While Peer to Peer is good, we learned at a large scale it is not good. Skype actually had to ditch Peer to Peer after it hit a few snags, and began to cause a major issue and a few large outages. While Peer to Peer has a great use for many things at certain scales, but it becomes a hassle once it hits a certain scale.
An example of this was when Skype finally had its largest collapse, a few "super nodes" as they called them went down and thus began to cause issues and become unstable and calls dropped, etc. We have to look to systems like the cloud and dedicated server, while we can use Peer to Peer in junction with them, we still need to rely on powerful strong connections. I don't want to sound dickish here, but Peer to Peer is amazing and I use it for a lot of things every since BitTorrent Sync was released, it still is kinda more of the "cost efficient" way to do things. Though that isn't always bad, I am just saying with Peer to Peer things can be done, but we need to mix it up like skype had to do by adding real servers people pass through now.