Let's bring this down to earth. You're confusing transit and peering connections. Netflix pays level3 for transit service (you pay your brother). Comcast pays

Let's bring this down to earth. You're confusing transit and peering connections. Netflix pays level3 for transit service (you pay your brother). Comcast pays level3 (your brother) for transit service. Notice how level3 is neither the source nor the destination of the traffic. Netflix's traffic increases from, for example, 500Gbps to 1Tbps. Comcast's level3 ports fill up because netflix increased in popularity. In general networks that pass a lot of traffic like this end up peering directly and avoiding transit costs. Comcast has two choices. They can either pay level3 for another 500Gbps or they can transition the full 1Tbps to free peering directly with netflix. And yes, I consider it Comcast's responsibility to do one of those two things with their subscriber revenue, which, incidentally, most other ISPs in the US are doing. Instead they are choosing option 3 which is, leverage their local access monopoly to force netflix to pay them, and protect their cable and xfinity services.