What also makes sense for a private company and, in this case, a publishing company is that they are liable for what they publish.
That means that people can take action in the justice system if they think a contract was broken or any sort of harm was made.
Unfortunately, that is not the case with these platforms. You can't take action against them because they are not categorized as publishers, but as platforms instead which do not make them liable for things that they would otherwise be.
Make Google, Facebook and other "platforms" into publishers and this problem is solved.