But you are leaving out an important part of this. The Networks are a monopoly, and they are protected. The rules are decidedly in their favor and to me they should be only thankful there is a system for them being carried.
I will believe you that the majority of people can get a signal, but that also does not tell the whole story. It still leaves chunks of people who can not. An extreme few in all of Eastern Ct for example can get all or often any of the Ct locals anymore since digital. Even in Florida, go much more north of Tampa than I am and it would not be easy to get them.
And then there is this. While many can technically get the signal, many are in apartment buildings making it very difficult, and many more simply do not want to bother with an antenna anymore. If no other choice more would try with an antenna I do believe but how many would just forget about the Networks and watch what they can online or with a Satellite/Cable subscription?