Here's the VP of Reddit's community cited in the article, Laura Nestler, preaching super engagement from a platforms most fanatical users to power content for the 90%.
She suggests, intrinsic motivators such as "autonomy".
I remember there was like a twilight where yelp was helpful, then it wasn't and I learned all their shady shit and went "yeah that explains it".
Reddit has a longer amount of content to burn through but if it becomes just husks of communities puppetted by corporate pr firms it's going to just slowly cannibalize.