Earlier quoted context omitted.
What you're probably looking for is closer to a closed discussion group or mailing list than "social media", which is presently universally-readable, algorithmically-targeted, feed-based, advertising-supported, and increasingly, saturated with AI slop (which itself has replace clickbait and ragebait). Which reminds me of Kitman's Law: Pure drivel tend to drive off the TV screen ordinary drivel. From Marvin Kitman htt…
I want my posts universally-readable and universally-interactable (that's why I don't like the idea of locking my accounts). I also want to be able to explore the social graph — looking at who follows who, what that friend of a friend posts, etc. It all forms an integral part of what social networks are. What I absolutely do not want is the platform having any of its own agency. I want a social network that ideally w…
Truth though is that today's Internet is vastly different from that experienced in the 1980s (when I first came online), '90s, aughts, or even the teens. Scale is a huge piece of this, though broadband, mobile devices, advertising, attention merchants, clickbait, and AI have all had their impacts. The Internet (or proto-Internet) of the 1990s and earlier was very limited in access, with soft-but-imposing barriers to entry (selective research universities, some government agencies, some tech firms), which made the experience both "open" and closed. Yes, there was exposure to a large audience, particularly as contrasted to immediate physical space or mass media of the time (print, including early small-scale copiers, amplified audio, radio, television, and telephones). But the total online population would be considered a minuscule social network by current standards --- a few thousands to a few millions of souls in the 1980s and 1990s.
I continue to use some smaller networks today (HN, Mastodon, Diaspora*), and find that they tend to retain at least some of the feel of the forums I was familiar with in the 1980s and 1990s: small, intentional, generally motivated. Ironically, their limited size and the fact that those who are there want to be there is something of a feature. A significant problem isn't so much people leaving as dying, which seems to happen with regularity. (An older population amplifies this, though I've noted previously that mortality at FB/Google scale is likely on the order of tens of thousands of accounts daily.)
The platforms I mention also largely lack agency, which as you note is quite refreshing. I'll note that HN is somewhat an exception, but it's mediated mostly by humans (member flags, moderator actions), as well as some automated rules, though those are largely guided by HN's mission of "intellectual curiosity" rather than attention-mongering.
Factors other than scale alone include broadband (enabling graphics, audio, video, and interactive content, all of which have considerable downsides), mobile devices (making for more distracted and far less nuanced discussion, as well as quite brief responses contrasted with physical keyboards), and the pernicious first and higher-order effects of advertising, manipulation, algorithms, AI, and the like.
I've toyed with the notion of a set of interrelated scopes, some limited and personal, some more widely open, though arranging that formally and as part of a designed system has yet to emerge. I have hopes for that though.
There's also the distinction between a pure social graph and a highly-curated specific discussion or forum. I've tried the latter from time to time with stunningly good results, especially at modest size ((This comment, as most of mine, was composed at a keyboard, and edited several times.)