I've used a lot of social networking systems over the years based on a lot of technologies. I deeply understand the nostalgia for blogs and RSS—I had a blog for many years and have used an RSS reader continuously since probably 2002. I still enjoy reading blogs to this day.
The problem with blogs, though, is that there is no great solution to limit the visibility to certain audiences. It really limits the types of things you can share. At least with Facebook, you can limit posts to your friends or groups of friends. But even that is not really practical—it's too much effort to have every person curate every other person they know into groups for access control (Remember "circles" on Google Plus? It didn't work).
I think the right model is to allow distributed communities to form organically and then use those communities for sharing permissions. By "distributed communities" I'm thinking of things like email lists, Discord servers, phpbb forums—communities where membership is symmetric and there is a shared sense of who is in the community. Blogs don't have anything like that.
> there is no great solution to limit the visibility to certain audiences
There's an important sense in which you are very wrong here because nothing on the internet is actually hidden. Everyone can see everything regardless of the visibility you think you've put on something.
But there's another sense here where audiences do tend to self select into groups and do tend to see and (crucially) engage with things in niches. The early web was very much this first kind of social network where we all could go and read random stuff but we all found niches that we fell in love with. This gained more structure (and convenience) with web forums and then perhaps MySpace and Facebook and other social media added even more structure (pictures only with Instagram, short messages with Twitter, video on YouTube, etc). The structure has also morphed so that these platforms all start to look a bit like each other too.
All this to say, for the "old web" to return, it would need to be as "structured" as the one we have now but give us back the freedom to build whatever really cool thing we wanted. I think the only way to do this is with progressive enhancement of some kind.
> There's an important sense in which you are very wrong here because nothing on the internet is actually hidden. Everyone can see everything
I'm impressed with how confidently you disbelieve in the field of computer security.