Reddit can pay mods, just like every other social network does. Not rocket science, and if they did it just for the top ones, wouldn't cost that much.
If this was even 1 year ago, things would be different. But it's not.
(I moderate a major subreddit)
There is something wrong with me that in the 90-9-1 rule, I need to be the 1%. I see a forum, and I can't stop myself from commenting or posting. Getting invited to moderate happens naturally after that.
I wish I was the 90%.