“Companies will regulate themselves” is a cute libertarian bedtime story.
I've never heard libertarians say that. Rather, they say that consumers have the potential to regulate companies if they choose to do so, by voting with their feet. We should do so more often than we do; when there's a free market (monopolies are not free markets) it feels pretty good to tell a company to go screw themselves.
[0]: https://github.com/a327ex/SNKRX/blob/master/devlog.md