Earlier quoted context omitted.
So, in the case we're discussing here (and directly applicable to my own situation BTW, but that's anecdotal), people will have the "choice" between, let's see... Comcast-TimeWarner and... Comcast-TimeWarner. Great choice, I'll take seven! Or I could choose to not buy, therefore starving myself of the resources they provide. That's even better!
So you really, really have to have Internet/cable, and they must give it to you cheaply and at high quality? If you're not even considering the option of walking away from them, you're giving them enormous leverage over you. EDIT: This is the behavior of "rational economic actors", IMHO. If the benefit you get from the expensive Internet they offer is bigger than the cost, it's rational to take it. If it isn't, then…
The 'rational actor' model is to economics what spherical cows [1] are to dairy farms. It is a simplifying assumption that is useful for certain general cases, but if you ever find yourself depending upon it in an argument, you're working at too shallow a level.
In this case, though, even if the rational-actor model were valid, you'd be wrong. In the case of monopolies and oligopolies, the rational-actor approach is to, basically, let yourself be screwed by the monopolist.
For example, in my case I'm in an area where I pay more money for worse broadband (ADSL) because I hate monopolists like Comcast. From an economics perspective, I'm an irrational actor, because I'm not optimizing for my own interests.