Actually, those protocols are becoming more and more attractive to those that provide legal downloads and applications as they reduce server load enormously. Apart from that, many open source and creative commons downloads have been available in this form for years. In fact, I just read a big America ISP retracted its policy of throttling p2p-traffic.
I wonder, though: Wouldn't this 3 strike policy have to be agreed with by the users? After all, it's a massive change in the contract originally signed. And what happens if you refuse to accept it?
It's far from certain they will succeed in implementing this. There's a bunch of obstacles to overcome first as you point out. I think they will run into big problems.
Not the least of which being that most of the ISPs are dead against it because it involves lots of effort n their part in identifying specific infractors, of which there will be many.