I know this is the inevitable and cliche pushback, but it never seems to be grappled with so it remains worth pointing out: none of the three things you mentioned are anywhere close to monopolies. There are lots of social networks (Twitter and TikTok are extremely successful, among others), lots of ways to search the internet, and lots of ways to shop online. The analogy with the railroads simply is not apt, their monopoly was so powerful because there was often no other way to get from point A to point B, so they had complete leverage. This is not the case for any of these companies you listed, there is a lot of competition in all these markets.

But I also think there are major issues with the current configuration of the tech industry! They just aren't because of monopolies. It is not helpful to misdiagnose a real problem. It is not helpful to have only a hammer and call every problem a nail.