Level3 and Cogent both bill the majority (by traffic volume) of their network consumers by utilization. This means that these congested pipes are actually costing potential revenue.
Obviously Cogent would be willing to cut off their own nose to spite their face, but Level3 plays a much more sane game.
Hardball by coordinating efforts of the backbone providers is somewhat thwarted by the coordinated efforts of the MSO's, some with their own backbones (VZ, AT&T). Cutting off Comcast would also invalidate a number of (government) customer contracts that require service 'to the full Internet'.
Obviously Cogent would be willing to cut off their own nose to spite their face, but Level3 plays a much more sane game.
Hardball by coordinating efforts of the backbone providers is somewhat thwarted by the coordinated efforts of the MSO's, some with their own backbones (VZ, AT&T). Cutting off Comcast would also invalidate a number of (government) customer contracts that require service 'to the full Internet'.