You wouldn't expect people who actually know about things to answer relatively low-level questions, answers to which are available in abundance already. I am sure you must seen the sort of topics people query/discuss about nowadays :/ .
Give them challenging and sensible open discussion and they will participate, and grow in numbers.
Apparently, we don't see many tech enthusiasts, hobbyists crawling the forums while showcasing their skills -at least not the way it used to be back in those days. No modders, hackers, and real techies - just bunch of wannabes roaming around throwing opinions as they feel.
I would love to participate in discussion, but I barely see any interesting topics worth the time and even if one does invest the efforts - it doesn't get going.