If enough Netflix customers live in Comcast-only areas, Netflix would have had little choice but to lean on Level 3 to capitulate. Even if the customers are willing to switch ISPs just to get Netflix, they wouldn't have had the option. That translates to less money for Netflix, more pissed off customers for Comcast, and a true win for nobody. With Netflix and Level 3 falling on their swords, their customers at least come out ahead in the short term.
In the long term, it's obviously disastrous. At some point, companies will have to refuse en masse to pay the protection money. In the areas where it has a monopoly, Comcast could stomach losing Netflix, but not another 10 or 20 big sites on top of it. There are antitrust issues with collective refusal to pay, but there's got to be a way around that.