I know this is an oversimplification and not even related to the OP, but it illustrates one point, unregulated private commerce doesn't necessarily lead to more efficient service (which would imply lower costs as well). On the left, unregulated private telecommunications and electricity. On the right, monopolistic regulated power and telephone services.
Perhaps a regulated private monopoly, like Ma Bell was, is the answer to building the best system. Or not. I don't know. I've always thought it was interesting in the early days of telephone when Company A wanted to talk to Company B and C, a private company would run a telephone like from Company A to Company B and another to Company C and so on until it turned into the mess you see illustrated on the left. I remain unconvinced that privatization is necessarily better than a government monopoly.