Calling the problems faced by social media simple is the sort of hubris that only comes about because of the Dunning–Kruger effect. You're underestimating the complexity of the problem because you're under-informed. Some aspects of your proposal have been tried before. They aren't new. History indicates that your proposal fails to achieve long term product-market fit. It also fails this entirely because of being decentralized and associating IP addresses with people and having high friction - not because of corporate dystopia.
Let's raise the level of discourse by reviewing our history. There are and have been in the past decentralized social applications. One of the most notable of them in terms of adoption was Skype. It was acquired by Microsoft. In the past it was normal to use Skype in gaming communities. It was a competitor to Ventrillo and TeamSpeak. Skype moved away from decentralization.
It's really common at this point for people who are simultaneously paranoid and outraged to start exclaiming with indignation that clearly corporations are evil. This failure to engage with reality is common online. Putting aside that social companies only discovered a few years ago that connecting people had disastrous consequence and have been devoting billions to try to address these so-called simple problems ever since it became clear these problems existed lets try to see if we can find a non-paranoid good-faith reason for Microsoft to have moved away from decentralization.
What do you know, but Discord displaced Skype for a reason within gaming communities!
Why did gaming communities move away from Skype? I've been in gaming communities. I've heard people express some of their problems with Skype. One of the issues that Skype had was that... it was decentralized and that could lead to the leaking of your IP address. Therefore if a streamer or even another person accidentally showed their Skype they could get DDoSed. At high levels in various competitive games this was a severe problem, because as you might guess... in social media you tend to be connected with people who are socially connected to you! So you leaked your IP address very often to just the sort of people with the incentive to capitalize on that by DDoSing you so they could beat you in a game.
Now Skype isn't decentralized, but it didn't matter. They didn't do a good enough job to serve some segment of the community. So Skype was doing just what you suggested. Being decentralized. And they had a higher friction process than a competitor, which is the case for your solution. And as a direct result of these things... (and others, mind, but we have to simplify reality at least a little to understand it)...
Discord found product-market fit in the gaming niche! And it grew increasingly popular. And now everyone in the gaming communities is on Discord, not Skype. Moreover, Skype has lost share even outside of gaming to Discord as Discord executes the standard niche to general playbook that so many social companies have found success executing.
Congratulations: your simple solution has already failed. You thought it was simple, but you were just ignorant of the actual challenges. But now we get to the real problem. The problem you completely missed. All of what I just said? It isn't the real problem. Those are details. They are suggestive of the real problem, but you need to step back and think about this from a level higher to see the true problem. It isn't technical. It is social. It's in the name. Not technical media, social media.
The true problem is so complex that it is almost certainly impossible to solve in a way which will please everyone. I'd go as far as to say it's probably fundamentally unsolvable.
Here is the real problem outlined using what we covered above:
1. Notice that decentralization is important to you.
2. Notice that it is outright against the desires of others.
3. Notice that social applications get more powerful as the number of participants increase.
Now lets generalize the above and make it more clear why those things matter:
1. Some people love X where X is something.
2. Some people hate X where X is something.
3. These people are incentivized to use the same application due to the utility of social tools growing with number of participants.
This problem is absolutely nutty in its complexity. It's also the actual reality of social applications. Almost all the issues with social applications boil down to the problem that people have different desires and those desires aren't in alignment with each other.
The technical aspects of the problem don't even matter. The problem isn't simple. As proof of this: mass murder and every other woe you try to lay at the feet of social media applications predates those applications. In actuality, the difference is that poor people have more power now relative to how much they had before.