If there's anything the modern internet has taught me it's that the Good Old Days were doing some things right! We don't know how to scale trust to internet-sized communities yet so a little tribalism may be warranted.
The way this solution solves the I Don't Know What I Don't Know Problem is by making you curate your own list of experts. For your example query, a colleague may have told you about a popular list that thousands of DBAs subscribe and contribute to. So when you search that query it has the sites to crawl and find the material