Ok my bad, microblogging isn't a bad concept. But its current implementations (besides twtxt and bonfire) conflate the last three use cases.
Microblogging may be good, actually, but Mastodon and Pleroma keep me hooked as well, make me aggressively look for excuses to get people's attention AFK, etc. (Although I'm reading 1984 and that's enough to get mad.) I believe the difference lies in the intents I put when I write something, i.e. that Pleroma makes me write to get someone else's attention. The UX makes it different here.
Maybe because attention on Twitter (thus on Mastodon and Pleroma) is deliberately scarce, which makes valuable contents hard to find. A pretty bad microblogging service if you ask me.