In my opinion, there's two reasons for this; first, Twitter has largely moved mainstream discourse to a superficial conflict-based format, even among those who might previously have enjoyed quiet reasonable discussion; a lot of these people are no longer going to get what they need, emotionally speaking, from a less confrontational platform. Second, the nature of Twitter has brought a lot of people into the mix who were not interested in participating in online discussion at all, but have been energized by the presence of a platform that provides an opportunity to dunk on jerks all day. These people, likewise, are not going to be served by a less-confrontational platform, and are going to move to the next thing or just disperse if no suitable platform is offered.
Twitter is huge; it's scaled for the kind of vast crowds that are attracted by the particular flavor of discourse it offers; if any significant portion of those vast crowds go away because it starts offering a different kind of discourse, then it will collapse under the cost and complexity of running a platform of that size.
I mean, the three threads with the most comments in the past week (by a significant margin) have all fallen under "rage-based engagement" (two threads on Elon-Twitter and the thread on Google Docs' new inclusivity checker). So while HN may be better in that regard, it is by no means exempt from that same influence.
People are inclined to argue in comment sections, and Twitter is one big comment section.
(It's also worth noting that HN enjoys its comparatively high signal-to-noise engagement because of its fairly heavy moderation; it seems self-evident what more "free speech" would do to that)
> If they get rid of the rage bait and toxicity
because AFAICT Elon wants to make speech more open on the platform, and when I hear that I think -> less moderation, which means -> more opportunity for rage posting, which doesn't really add up in my brain.
Yes, but being an international speech platform is a massive liability. And when you take a role of an arbiter of what politicians and MNCs can and cannot say you have to navigate thin lines. Just look at the chart of its stock price since IPO to see that its success is not financial. It’s basically a place for first-hand short-form news and for pretend-journalists to do “research” and pad their articles. Oh, and for overly online people to argue about controversial topics.
Twitter is so fantastically successful because they've created a platform that both feeds their users a constant stream of enraging content, and more importantly, incentivizes the creation of content that's enraging to someone else. In the process they've managed to mold almost the entirety of mainstream public discourse into an endless supply of hot takes, sick burns, and us-vs-them polarization that results in Twitter being an essential tool for anyone who wants to participate.
If they get rid of the rage bait and toxicity, then people won't need Twitter anymore and will move on to whatever new platform provides it for them.