It's government sponsored monopolies.
Local city governments control what cable companies are in particular neighborhoods. If you're lucky, there will be two choices, but I know neighborhoods where there's literally a single option. You might say, aha! Two choices means you can switch and do have some power here. That's false, as when there's only two options what happens is the two wind up behaving identically when it comes to things like this. There's just not enough competition to give real choice here.
Of course, there's smaller ISPs often available, but being smaller they are usually not services that can really compete with the others. This means the big corporations and the government can all claim there's no monopoly, while the end result for consumers is that there might as well be. Where I live, I have exactly two real choices (AT&T Uverse and Comcast), one pseudo choice (Dish Network) and one or two mom-n-pop non-choices. Because of the realistic two-choice situation, AT&T and Comcast both do draconian anti-consumer stuff all of the time, with no worries that they'll lose any customers. Sure, some might protest and switch, but roughly the same number will do the same to their competitor, making it a wash.