I think people have been demanding this for ages but lobbying by social media companies against any change in the law is enormous.

As for the cost of content moderation, Meta has zero interest in any type of moderation to begin with. The cost is just a public-facing excuse. In Careless People, Wynn-Williams mentions that Facebook didn't do anything to stop anti rohingya posts in Myanmar because they did not have any fact checkers who could read Burmese. In other words, they did not have a single moderator in the damn country.