This downward trend makes me wonder where is all that traffic going to? Surely developers are still searching for answers, where are they finding them? It can't only be ChatGPT since the trend started in February 2022, but it surely is a really strong contender now.
For me at least, I often go directly to the official docs. They're much better in 2023 than they were in 2013, pretty much across the board. And if that doesn't work, it seems you're more likely to find your specific problem being asked in the issues of the official Github, Gitlab, etc. than you are on SO. Even Reddit and some language/technology-specific forums will have better results now.
The fun thing is... I think SO saw that coming. They made that huge push to be the central documentation hub for everything from huge projects to internal teams. It just wasn't well thought out and expensive iirc, and had an abysmal adoption rate as a result