Libertardians obviously hate it when they're presented with evidence that the invisible market fairy doesn't fix everything [google.com].
I find it more interesting to consider why it doesn't generally work that way. I have only one answer: we care a HELL of a lot more about immediate convenience and instant gratification than we have ever cared about being consistent with our principles. So we'll buy from abusive companies that deliver poor service before we'll do without their products/services. We'll patronize a company that is known to engage in extremely dishonorable business practices so long as their products are 5% cheaper than the competitors'. The market idea really could work, except that it requires a people who are both more noble and have a far stronger backbone than our general population. Such a people would individually and voluntarily refuse to ever support any business that takes actions which are not in their interests, at all costs. In turn, the corporations would understand this which would both raise the general standard and guarantee that actually proving this to them would be a relatively rare event. But we want our shiny and we want it now and we don't care what sort of behavior we are rewarding by voting with our wallets. That's the only reason it doesn't work. There is none other. Corporations cannot act against our interests except that we provide the funding by which they do it.
They don't have to be "noble" if they have another cable provider to choose from.
A lot of people are saying this -- why try not having cable? That's a valid option.
You have a tendency to feel you are superior to most computers.