First, 20 years ago, in 1997, it wouldn't have worked. Hop in your time machine and go back and ask random people on the street how many of them want to pay a monthly fee for "internet access". Follow up with a bonus question of which they'd keep if they had to choose, TV service or Internet.
Second, you are right, Comcast would have loved to turn the Internet into cable TV five years ago, and as a member of the protected oligopoly, they would be in a good position to do so, except... oh yeah, net neutrality regulations prevent that.
Third, now that we are in modern times where most people do use the internet, it already has occurred where no preventive measures exist. There are examples in this very thread; click them.
Second, you are right, Comcast would have loved to turn the Internet into cable TV five years ago, and as a member of the protected oligopoly, they would be in a good position to do so, except... oh yeah, net neutrality regulations prevent that.
Third, now that we are in modern times where most people do use the internet, it already has occurred where no preventive measures exist. There are examples in this very thread; click them.