I mean, it depends on the sub, but if you expand your definition of "teenager" to include "36 years old, but still emotionally a teenager", then I think you are right.
In my experience, any subreddits with general appeal suffer from the same problem. Just find your niche/hobby subs and stick to them. Stay away from r/pics, news, etc...
You can still have tiny kings in small subs - mods with <10k members who let that "power" go to their heads - but it is more rare.