You just need several billion dollars of investment to dig your own cable to each of the customers and then fight each municipality to actually let you dig those cables while Comcast is lobbying hard against you :)

I think you'll find it easier to get hired as a manager at Comcast, then use political shenanigans to replace the HR department with a trusted posse of like-minded individuals and following that replace all of management. Then you can upgrade the physical infrastructure and to do that, lobby for laws that will allow other companies to easily install their own.

There are: netflix and googlefiber.

One is hamstrung by datacaps, the other by politicians, many of whom have campaigns funded by comcast.