P2P and Oversubscription are natural enemies
P2P traffic mitigation techniques are not going away anytime soon. Broadband networks are built to accommodate "normal" traffic patterns which have random bursts that tend to balance out the load. That's how with a single 38mbps downstream channel cable companies are able to provision multiple 16mbps connections with everyone appearing to be able to hit their maximum transfer speed.
P2P software operates under the assumption that there's all this "idle" bandwidth available to be tapped for transfers. The problem is that on an oversubscribed network your "idle" capacity tends to be your neighbors' "use" capacity. For being a "free" method of distributing content, P2P has expensive implications on capacity planning and network architecture.
There's only a few approaches to take with this, and any option that gets chosen is going to be unpopular.
1) Throttle traffic types that disrupt the experience for the overwhelming majority of your customer base
2) Convert to a usage-based billing system to fund infrastructure upgrades in areas where heavy use occurs
3) Increase the rates for everyone so that the oversubscription ratios can be lowered.
Thank you for a well written post.
It is true that BT is heavy in net use; optimally, content would be distributed in a less burdensome way. However, protocols and business practices for such more optimal distribution have been very slow to be created and meet each other. Business practices overcompress with suboptimal codecs and overly low resolutions and bitrates and other problems and generally set the quality standard too low, and have incapable pricing models (advertising vs. pay per use, and supposed cream-skimming which in fact simply bankrupts various PPV attempts with all of the Libertarians quick to support such attempts), and distribution models follow suit, being designed not to be the most efficient, but instead designed to be the most efficient at what is left over, which generally is much different, and not so efficient, but does well what it is designed to do (i.e., the current BT situation).