Strategic silence is truly an underated tool in the arsenal of true CM. In my farming days, I've seen like 90% of communities I've joined not pass the three-month mark. It revolved around one or two persons. The moment they are inactive, the community goes into solemn silence.
Funny enough, I unconsciously applied this method in the last community I managed (VIETDOGE). We had about 5-10 regulars who we rewarded with some roles, that basically answered a lot of questions. I only had to step in when there were errors in their answers.