I think the bigger reason they don't have competition is due to the crazy requirements to become an ISP / cable service for any city in america. You need to me

I think the bigger reason they don't have competition is due to the crazy requirements to become an ISP / cable service for any city in america. You need to meet with EACH city and sign a "franchise agreement", which specifically spells out what kind of service you will provide and who you will provide it to. This includes you providing a certain amount of bandwidth for local access / public access channels. It probably also includes promising to service 100% of the city and also whatever pet project the council has (wire up low income housing, provide 1GBPS service to the mayor's uncle back up in the woods on the edge of town, etc. etc.). Don't forget the public gets to comment, critique this entire process. Jane the cat lover can show up and demand a 24/7 cat pictures channel, if enough of Jane's friends support that, its going to the franchise agreement. It sounds like a good process in theory, but it just ends up getting super bogged down. Comcast are the masters of negotiating these things, they have teams and teams of lawyers who do nothing but get these setup.