So many good answers here, all converging on moderation overreach stifling the page before LLM came in.

I'm not disagreeing at all, but I'd like to add that the moderation issues did not come from a vacuum: they were a reaction to SO reputation becoming so much of a CV optimisation metric that SO must have felt a lot of pressure to do something. Turns out that something wasn't good, but I'm not sure that other paths taken would have been much less bad. Some success just aren't set up to last.