Blog post by Christine Lemmer-Webber, co-editor of ActivityPub: https://dustycloud.org/blog/how-decentralized-is-bluesky/
The likely answer to this is that there will always have to be a large corporation at the heart of Bluesky/ATProto, and the network will have to rely on that corporation to do the work of abuse mitigation, particularly in terms of illegal content and spam. This may be a good enough solution for Bluesky’s purposes, but on the economics alone it’s going to be a centralized system that relies on trusting centralized authorities.
Do I consider book authoring to be social media? No. That's mass media. Single origin, broadcast destination. At least once books started being printed industrially and sold as commodities. The definitions of these things are not new and are pretty well established.
And it had its share of fundamental changes compared to prior communication methods. People died. A LOT of people died.
Now, I used to think the people at the time saying print was bad and had to be controlled (and there were many) were the equivalent of modern social media naysayers and the Internet would bring a similar expansion of human consciousness past the growing pains.
I started being less sure about that maybe halfway through last decade and I was pretty convinced it wasn't true during the pandemic. Didn't even need the whole Musk/Trump stunt to get there. I don't necessarily think we can go back but I also don't think that the upsides are nearly as many as with print. Plus a bunch of the people that are gonna die this time are not dead yet, so I have a bit more empathy for them.