The gems on Reddit are almost all small subreddits with a community feel. I'd be virtually certain that its high user engagement is primarily driven by users who've matched into smaller subreddits that closely align with their interests. The big, default subreddits are largely wastelands.

But Reddit the platform seems to entirely ignore this dynamic. New users are dropped into the default subreddits, and there's very little tooling or onramps to help them find small interest-matching subs.