Firstly I don't think you understand the business you are trying to disrupt. YOU may not watch particular channels e.g. Fox but others do and they help to subsidise the unprofitable channels. So trying to break apart the channels will be impossible without a deep understanding of the economics of each individual channel and how that relates to your ability to sustain a profit.
Secondly it is widely rumored that Apple will be building a TV that offers an a la carte model. So something to be mindful of given how well their products sell.
Thirdly if the top two don't faze you then there is the fact that you picked a problem that is extremely high cost, low margin and with players who seem to get a kick out of destroying competition through financial and legal means.
But hey by all means give it a try. You learn more by trying and failing than not trying at all.