Most of the easy questions have been asked. I stopped using it because I was asking questions that weren’t trivial to answer, and I guess it is easier to earn internet points through mod actions than through writing answers.
As my career progressed I took on deep problems with complex issues and complex answers. Not much sense in asking as no one ever managed to help me with them. I’d just end up answering my own question a week or a month later perhaps.
And of course the moderation and karma farming - I oh so ‘fondly’ remember the one user that would take your question and run some auto-formatter on it so that it would fit his personal style guide and then get a percentage of the points as your now “co-author.” What fun!
It stayed useful as a reference tool for quite a while, for when I needed to look something up that was fairly common but that I wasn't personally familiar with. But as others have said, the way they handled dupes and supposed opinion-based answers was really poor and meant that the top answers got more and more out of date each year. By the time LLMs came around they were strictly better for those kinds of lookups. Strictly better for now at least, LLMs will themselves get enshittified in the coming years.