When I tweeted this two years ago, r/sleep had 80k subs. It now has 530k+! New prediction: r/airquality is up next. The subreddit only has 4k subs, but already doubled in last 6 months and I think will explode with increased awareness & tracking, plus escalating wildfires.
We're also still earning innings. Simple example: r/sleep has 80k subs, while r/meditation has 700k. Not everyone meditates, but everyone sleeps! It may even become a recession-proof industry, like supplements or pets, as ppl develop an insatiable appetite to optimize for it.