While the criticisms of the moderation systems are surely valid, AI definitely killed Stack Overflow. The metric the article authors chose to indicate the pre-AI downward trend was questions asked. This will naturally decline as the body of existing already-answered questions increases since many developers will have similar questions. The steep drop post-AI is different and reflects the ability of LLMs to answer a large fraction of the sort of questions people would ask. I would think a drop of traffic (as opposed to the questions asked) would be a better metric but I can't find one that seems reliable.