In this world, the ISP is responsible for distributing the money to the content providers that we accessed.

I realize this implies that your ISP has to track you, but that is not news, it just puts more responsibility on it. I also realize that there are some logistical nightmares as well: e.g. if you go to a friends' house that spends all his money on toy cars, you will have to enjoy diner over some nice soothing music and ads for cholesterol medicine. But this can be solved if you implement a RADIUS-like framework across the internet, where you authenticate to your bling-bling account from everywhere (like eduroam).

This is an idea and I would like for us to try to attack it from every side and see if it stands :)