That's probably why the number of new questions asked dropped off. Once someone has asked "how to fizzbuzz in python", that's pretty much it. You'll get the textbook answer, the "why are you fizzbuzzing in the first place" answers, and then an answer a couple years later using the new python fizzbuzz built in library. You have a massive compendium of questions and answers and for most people, that's good enough. I don't think that stack overflow was necessarily less popular in visitors pre-LLMs but they certainly killed it off quick.