In the same vein, freediving is easy to learn up to a certain point and safe as long as you don't hyperventilate and stay away from caves. Most people can learn to dive to 10-15m and look around a bit before they have to resurface. That's far from breaking any records, but enough to have fun and see some cool stuff that you can't see from the surface.
Plus, you don't need any special gear, besides snorkel, mask and fins.
I didn't fully quit reddit, but I'm going to Lemmy first and foremost and rarely go back to reddit for very specific communities. My reddit usage dropped by 90+% probably, but I'm not completely gone.
I'm sure the same is true for many other users as well, so simply counting the number of (active) users then and now won't get even close to the actual loss in traffic and participation.