I've been thinking about this more. If all non-commercial IPs were firewalled, many services like Skype, Game Servers, Messengers, or IRC services hosted on a commercial level service could still remain quite usable with little or no adaptation.

From an anti-p2p point of view, internet connectivity would have to have a large enough price gap between commercial and non-commercial accounts for this to work. Otherwise most people would just cough up a little more money for control over their firewall.

Regardless of pricing difference, it would still be easier for ISPs to recognize those participating in PC to PC communications involved in networks known for piracy. In the past this was not a big deal. But with more court cases against ISPs resulting in client piracy also being the responsibility of the Internet Provider, this will likely become more of an issue to some degree.

Even though it is highly unlikely that non-commercial forced firewalling would become common policy, even with such a state P2P networks could still be maintained with a high rate of success. I don't want to make it seem like a cakewalk, but it would be possible with higher network maintenance. Even if none of the participants had a commercial (non-firewalled) service.

I then thought of another kill switch. Again all commercial services could easily adapt with little effort. But even a network that managed to circumvent forced firewalling would have a very hard time circumventing this in addition to firewalling. Dynamic IPs with an hourly refresh.

Any network surviving this would have to in someway or another rely on a commercial service. Like chatroom or email. But it could still work. The problem then seems to be hinged on how the governments of the world look at encryption in light of recent political controversies. If email was relied on for connectivity (in this imagined world of forced firewalls and dynamic IPs) the data for connectivity would need to be encrypted to remain somewhat reliable. The reason being that email providers (and any commercial service in general) would be held responsible for contributing to P2P networking. The only way to protect services like that would be to prevent them from knowing their service was contributing as much as possible.

With this whole imagined scenario all hinging on encryption this brings us to the possible future legality of encryption. One political position on the plate is that encryption would be legal, so long as the government(s) (including "Law Enforcement") have exclusive access via back doors. With law enforcement having access to the networks connectivity (tunneled over a service like email) all that would need to be established it that the network is used to pirate data. In such a world it might even be enough that the network could be used to do so.

If you have made it this far, please keep in mind that I intend this as a thought experiment.