I think you are severely underplaying the massive role social media played / plays in peoples usage of the internet. To a lot of people it "is" the internet as

I think you are severely underplaying the massive role social media played / plays in peoples usage of the internet. To a lot of people it "is" the internet as far as they know. It is very likely there is never an explosion of usage if not for social media which in turn would effect how much money and time was invested in all of those other things you mentioned. Also I don't think you can definitively say that search engines and directories would not be effected, if they indexed some sort of illegal content they could very like have been sued for linking to it.