As someone that spent a fair bit of time answering questions on StackOverflow, what stood out years ago was how much the same thing would be asked every day. Countless duplicates. That has all but ceased with LLMs taking all that volume. Honestly, I don't think that's a huge loss for the knowledge base.

The other thing I've noticed lately is a strong push to get non-programming questions off StackOverflow, and on to other sites like SuperUser, ServerFault, DevOps, etc.

Unfortunately, what's left is so small I don't think there's enough to sustain a community. Without questions to answer, contributors providing the answers disappear, leaving the few questions there often unanswered.