Short post and I don't have the math background to go into this more rigorously, but just going based off intuition.

Media platforms that create a single giant graph with tons of nodes and edges give rise to emergent dynamics that humans did not evolve to deal with. The worst voices get elevated, polarization increases, and we get phenomena like memes and virality. I think these create misaligned incentivizes.

Humans do best in strongly connected networks of up to a few hundred. The networks are then loosely connected to each other. There is high trust within each cluster because everyone knows everyone, which significantly reduces the risk of polarization, and also moderates the most extreme voices and egregious behaviors. Members of different clusters can interact with other clusters, but not arbitrarily: there is a time and protocol for doing so.

This is how tribes, villages, and towns interacted with each other for thousands of years - not one massive public square. I think a digital network organized like this would be much healthier than modern social networks.