Longer conversation than I'm willing to go into here, and I assume that you already know this anyway, but this is a point that Cory Doctorow pushes a lot. His take is that sites like Facebook in particular got where they are because they were able to scrape and remotely manage other sites, and that after they rose to dominance (among other things like buying competitors) they also pushed to shut down a lot of those systems and make it harder to do what they did.

I'm interested in seeing how EU legislation works out here. I tend to sometimes be relatively skeptical about EU legislation because I think the final results tend to miss the mark or get compromised or have side-effects, but I have seen a lot of people that I respect a lot say that this legislation is good, so I'm really curious to see what happens with it.

I don't personally think that network effects are the only thing that's factoring into current tech dominance -- my evidence for that is that Facebook has had to buy competitors before, and I don't think they would have felt that threat if they were confident in network effects alone to save them. I've also gone through enough internal emails from the various leaks from Facebook to where I can see some the anti-competitive strategies they tried that (in my mind) were in a very different category than just locking down an API. But network effects are certainly an important part of the puzzle, and even ignoring the market, having more user agency to remotely control accounts and build/use their own clients for services is (in my opinion) a really important part of individual freedom, so I'm all for improvements in that area.

And highly agreed, the problem with Facebook is not that people want to talk to friends and family. I don't think that people's instincts to be connected to each other should be treated as something that's unreasonable or bad.