Similar here. I don't share your numbers, but I had ~10,000 on SO and ~5,000 on Cross-Validated.

I started it as a way to learn things. Mostly picked questions that were on the edge of my understanding, researched the problem for myself, and then tried to provide clear and detailed answers. So I got a lot out of it too.

My view for when SO started to decline is also similar to yours - being flooded with poor quality questions. And on average people asking questions became more arrogant, put little effort in, and demanded the whole place to change so they can paste their broken code and have someone fix it for an upvote.

So I think I naturally and slowly drifted away from using SO. However, publicly stated reasons for SO's downfall often proclaim there was something wrong with people who answered questions. That they were rude or were "gatekeeping". I always feel alienated reading those, since it's very different from how I experienced the site.

Kudos to you, you're a more helpful person than I. I never looked for questions to help people, my interaction with SO was always "me first". If I had a problem before the AIpocalypse, I'd look on SO. If I couldn't find an answer I still had the problem and would have to figure it out the hard way. And once putting in the effort finding the answer it was little additional effort to provide it to others.

So I ended up with a large number of "revival" and "necromancer" badges for getting upvotes for answers on old previously unanswered questions. And many of my questions have my own answers posted a couple days later.

IOW, I provided a lot of value to SO. But I got even more value out of them, finding many more answers than I provided, especially since many of my answers were for very obscure questions. A real significant win-win.

I think this would have been a better model for SO -- encouraging more of this sort of drive by helpfulness rather than gamifying/socializing so much to encourage direct helping.

I became active on SO late (2018) and now have 6K reputation. Providing good answers to new questions was worth basically nothing. No one upvotes you.

90%+ of the upvotes come from super old questions that have been around forever. Google indexed them and sent traffic there. Old inactive accounts get 1000s of upvotes a day and if you weren’t active when Python 3 was new or when Apple released Swift or whatever then trying to build reputation felt like a waste of time.

Contrast that with Reddit: commenting on new posts is the only way to build karma. It incentivizes new activity.

My reputation is 49,636 (I was a relative expert in iOS and git when both technologies were young, and answered a LOT of questions that are still getting upvoted to this day)

My last answer was December 28, 2015, and corresponds pretty closely with me getting a more interesting and engaging job. That, and the two areas I knew well were maturing and there were a lot fewer easy questions to answer.

My working theory is that being able to understand a detail answer itself requires a certain level of understanding for that topic. In that absence of that it would throw off a big crowd which was hoping to find something simpler, something that aligns with their existing understanding easily.

Totally agree, my last answer was also in 2021; I remember trying to jump back in and just feeling like the quality of questions was so poor and all of the many "homework" questions felt dirty to answer because I'm clearly helping someone cheat.

I actually got hounded / insulted on a couple of my last answers for not providing timely responses to their comments on my answer and that was the last straw.

Never ending September?