Notice how almost none of the service areas intersect? Internet competitiveness in the US is measured by census zones, and they know that. So they carve up territory block by block, allowing them to be engage in "competition" without competing. (https://arstechnica.com/tech-policy/2017/10/isps-dont-want-t...)

And here's one of the many, many court cases and lobbying efforts they've engaged in to keep rivals from getting a toe hold in their territory; https://www.theverge.com/2015/5/1/8530403/chattanooga-comcas...