It is wrong, but so are you. The truth is that social networks are big because they HAD genuine utility. The Facebook was amazing... at least until about 2010. I was at uni when it started and I vividly remember thinking "I wish there was a website or something that would help me know who everyone is" (we didn't have physical face books in the UK) and then a year later thefacebook turned up. Amazing for everyone's social lives.
But after 2010 it just gradually got shitter.
WhatsApp replaced it (in most ways; in some ways there is no replacement) and has so far been amazing but it feels like we're about at the "2010" of WhatsApp. Meta is starting to turn the screws. An AI button. Notifications about new features. Integration with Meta accounts. Eventually it will probably merge with Facebook Messaging or some bollocks and then we'll all have to move elsewhere.
Anyway my point is, these things genuinely became big because they were great. They stayed big despite becoming shitter due to network effects.
> I wish there was a website or something that would help me know who everyone is
Did you miss Myspace and Friendster? Orkut had a market, I think. The reason that Facebook succeeded later is because it had a good API and invited people to write apps for it (mostly surveys and games, remember Zynga?), tracked its users across the internet, and sold them in targeted slices to advertisers. It was Friendster as a commercial platform (like Salesforce was CRM as a commercial platform.) It was never any better than Myspace, and gradually got much worse.
I have no idea what you think is or was so great about WhatsApp. It was successful largely because it had no overhead and infinite throughput, being created by very talented people using Erlang. The reason people use it is because they always have and their friends do, and for a lot of countries with expensive SMS it provided messaging (and became so integrated into business that people weren't allowed to live without it.)
This is my argument about why these things were successful; I think that "they were great" isn't a credible one. They simply grabbed a large chunk of already proven markets quickly, but oriented themselves toward corporate needs to leverage that into total control.
Also because they closed all the gates of interoperability once they got big enough.
If they didn't have the incentive to get a monopoly we would have kept a more decentralized web.