> they're going to have to upgrade just a few spots with really expensive equipment just to deal with Netflix traffic
You're missing a key element of the situation: Comcast made a deal with Netflix precisely to address this problem. Netflix now has direct connections to Comcast's network, so Netflix traffic does not have to go through a third party. In other words, Comcast now directly controls how they connect to Netflix, how many connection points there are, what the average network distance is between the closest Netflix connection point and their customers, etc. So they have a much cheaper way to even out Netflix traffic: open up more connection points.
(Which, btw, AFAIK they already did as part of the deal; they certainly did not come out of the deal having "just a few spots" where they are connected to Netflix. Netflix basically is their own CDN; they have servers with their content on them all over the Internet. So Comcast has all kinds of ways to shorten the average network distance between each of their customers and the closest Netflix endpoint.)
You're missing a key element of the situation: Comcast made a deal with Netflix precisely to address this problem. Netflix now has direct connections to Comcast's network, so Netflix traffic does not have to go through a third party. In other words, Comcast now directly controls how they connect to Netflix, how many connection points there are, what the average network distance is between the closest Netflix connection point and their customers, etc. So they have a much cheaper way to even out Netflix traffic: open up more connection points.
(Which, btw, AFAIK they already did as part of the deal; they certainly did not come out of the deal having "just a few spots" where they are connected to Netflix. Netflix basically is their own CDN; they have servers with their content on them all over the Internet. So Comcast has all kinds of ways to shorten the average network distance between each of their customers and the closest Netflix endpoint.)