I think it's the opposite, and that all these can easily be achieved together. Instead I believe that the difficulties with running social media companies come

I think it's the opposite, and that all these can easily be achieved together. Instead I believe that the difficulties with running social media companies come from not wanting these: there's a desire to control narratives, to push advertisements and to have central control. If these are the requirements the result is a behemoth of a company, which must do a great deal. Meanwhile, if you have something noncommercial, where you just want some kind of forum where people can communicate with you and others, you can let them filter as they like, turning the knob down on any kind of spam-- because the user is running their machine and getting the benefit of the communication they desire, there is no need for any centralized control of the information flow-- the user decides what he sees, nor any need for advertisements, and because of the absence of advertisements there is no need for censorship or control in that regard. Furthermore, because messages are public the difficulties with dealing with things like e-mail spam disappear-- you will simply see what people think about a certain message, and you will not decide to see it if people in the tree of people you like like it. I think internet technology is ready for this kind of thing. It's a bit of work though. To make a distributed WebRTC-Reddit where even people on phones can contribute to the communications network is a bit of work, but, I think, no longer infeasible.