said by socrplyr:P2P works by opening up 10s/100s of TCP connections
But P2P protocols only transmit data on 3-4 of them at any one time. (The rest may remain open and idle or may be disconnected after exchanging a small amount of overhead data.)
This overlooked reality breaks your conclusions.
The advantage, if any, is not 10x or 100x, but only 3x or 4x. (And it's not even that sometimes, since it's unlikely those 3 or 4 connections all follow the same route and will experience the same congestion.)