These are some very good points. For me the biggest problem with existing social networks is how difficult it is to get to know new people through the applications. Despite us spending more time online than being present on the physical world (this is probably also a problem, but one for another time), we get remarkably little real social interaction out of these hours spent.

Good news is that the seeds of better social do exist. I'm trying to set up one of them, http://www.reason.so/ which will match people with similar interests into small (3-10 people) group chats with the intention of creating small communities where it's easy to discuss things you find interesting semi-privately (i.e. somewhere between a public Twitter thread and a private group message). By keeping the chats small you also get rid of clickbait, astroturfers and "thought leaders" who only want to build an audience instead of actually interacting with other people.

The biggest problem with setting up a social network like Reason is probably monetarisation. People just aren't ready to pay for social media when Facebook, Clubhouse and co are free.