Was that ever not the case? Was there a time when any person with any message could reach the whole country with their message? The scarce resource here isn't

Was that ever not the case? Was there a time when any person with any message could reach the whole country with their message? The scarce resource here isn't freedom of speech, it's people's attention. As always, you can say whatever you want, and as always, it's hard to get people to listen to you. Before the internet, you basically needed an already-famous person to take an interest in you in order to get noticed. Now a message can go viral organically, without needing to involve any journalists or talk-show hosts, but the platforms are free to stop something from going viral if they don't like it. Facebook giveth and Facebook taketh away. But to answer your question, I think breaking up the platforms would be a better solution than treating them as de-facto public services and trying to regulate them as such. Or appropriate them and make them into actual public services :)