I think you are mixing up two things here -- market dominance and free speech. None of these companies were regulated in any way with regards to the 1st amendme

I think you are mixing up two things here -- market dominance and free speech. None of these companies were regulated in any way with regards to the 1st amendment. These companies were regulated because of market dominance. It isn't efficient to have 2 electric or 2 telegraph or 2 phone companies when they were established -- so government set a reasonable profit margin and then drew up rules by which the companies had to abide to stay in their position. (I'm guessing bus/plane was more about not crowding others out, as they don't have the sunk costs or moat that the other companies acquire by their nature.)