[dllthomas]

As others have said, Comcast is also being monetarily rewarded here. I think the best argument lies along "the sender is in the best position to take measures to reduce traffic (traded off against their goals)."

[exelius]

They are rewarded for providing access; not for passing individual packets. There's a difference.

[dllthomas]

How precisely are they providing access if they do not pass individual packets?

Edited to add: It's certainly true they are not rewarded for the marginal packet, but then neither is Netflix (given their subscription based model).