But the person who makes the decision as to what ends up in the pipe (i.e. the end user, Netflix doesn't just spam people's routers) is the one who is already p

But the person who makes the decision as to what ends up in the pipe (i.e. the end user, Netflix doesn't just spam people's routers) is the one who is already paying. Netflix isn't crowding anyone out (especially if they have a server within the ISP's perimeter), every bit of that bandwidth is requested by a user. Users crowding each other out is already handled by prioritizing based on how much they pay. Mass of food is a false equivalence; cost of food per kg varies widely based on food, but cost of transmission of bulk traffic (the only kind ISPs are proposing to charge the entity on the other side of the connection for) is largely identical to the ISP. The cost may vary depending on where it comes from (network wise, not precisely geographically), but ISPs are already able to deal with that by having different sized links to other ISPs.