Obviously breaking it into 1000 mini-comcasts, like AT&T, wouldn't, by itself, do anything useful. I think the unstated assumption is that in addition to break

Obviously breaking it into 1000 mini-comcasts, like AT&T, wouldn't, by itself, do anything useful. I think the unstated assumption is that in addition to breaking up Comcast, you'd also break the franchise agreements in order to allow competing cable companies within each territory. It's very difficult for a start-up cable company or ISP with an innovative product, say, a la carte pricing, to get going because Comcast can undersell them (or offer the same innovative product) for as long as it takes for the start-up to burn through their capital. They can do this because 1) The start-up's limited capital prevents them from opening in every market at once; and 2) Comcast's national presence allows them to use the profits from one region to subsidize service in the region where the start-up is competing. It's probably cheaper to just buy Comcast than to try to beat them in a race to the bottom.