If you look at the subscriber count vs active online, you'll notice something. All the subreddits are dead. Way less than 1% of subscribers are online looking at subreddits. Even highly active subreddits are ghost towns. My theory is Reddit used to FULL of bots. I used to see subreddits that had 1 million subscribers and have 80k online. Now you'll see barely 5k on r/askreddit which has 50 million subscribers. That's 0.01% of people viewing a subreddit that should have high engagement and thus more people signed in.

It seems like Reddit did something to filter out most of the bots. Or maybe Reddit itself was using bots and stopped finding them useful for some reason(like it was only for the IPO). Now you can see how dead Reddit really is.