I love writing documentation too, but from years participating on Stack Overflow I found it most unreliable for the purpose. As I once quipped, "Imagine Wikipedia where there are several hundred articles on the New York city. And one that Google links first is copy-pasted from Encyclopedia Britannica, 1913. And every single day several kids from elementary school start a new one."
SO is torn between essentially ambiguous goals, providing fast on-site answers and being a reusable knowledge base. And it's good with the latter only because of Google. Without Google it will be no better than fast on-site answers on Slack.