I still think SO was done in by the weird way they handled similar questions. Then encouraged veteran users to flag new questions as dupes, even if the "original" question was years old and unanswered. Who does that even help?

Imagine if the system had let veteran users link a new question to an existing answer rather than a question, and if the asker finds it solves their problem they can accept it. At least that way new joiners would have a chance of getting their question answered.

Looking back it feels like SO was one of the first really gamified sites, and the people running it got weirdly focused on the point-economy aspect. They ran the site almost like "points" were a finite resource, and not to be handed out unless the user really deserved it.

The vast majority of duplicate closures use already answered questions as duplicates. So ideally that question should have answers that apply to the new question as well. In my observation this is usually the case, though the answer might be more generic.

I have also seen bad duplicate closures that weren't actually exact duplicates. But people talk like this is the only kind of duplicate closure that actually happens. I've no idea if the rate of bad duplicates is so much higher than I observed, or if people are missing that their question is actually answered in the duplicate.

I will say, moderation is a valuable thing on websites that intend to be useful for people. Wikipedia being another example. Ynews also has moderation.

Sites like Quora don't have good moderation (nor social media sites) and they become less useful for "how do I do X" questions.

LLMs do the moderation of the underlying source and just give you the answer.