I think that people are arguing for rules that ISPs must abide by. I doubt that anyone is arguing for ISP monopolies. While people are arguing that there ought to be regulations on what people are paying for, it seems as though very few people are arguing over what they are actually paying.

It is also worth considering that five competitors is not a very large pool. (They even have a word for it: oligopoly.) In many parts of the U.S., there are even fewer options because there isn't the population density to justify building out the infrastructure. In other words, competition doesn't work as well as we are led to believe. That is particularly true for industries that are difficult to enter into due to the infrastructure that must be constructed.