Maybe I am too harsh, and measured by its usefulness[1] it is not really a failure. I was involved in the early SO community and I think it is failure compared to what it could have been.

[1] However small that may be, even I would have a hard time to argue that it is useless or irrelevant.

It was quite successful.

(past tense)

I fear you might be true. I do worry though that a big reason LLMs are good and answering tech questions is that they’ve read SO