Are there niches on Youtube that pay in the $20+ range?

Not sure. I'm only concerned because it sounds like youtube red, but only youtube red. People paying money will expect higher quality content. Someone joining the site as a creator with little money won't be able to afford the flashy style expected. Your best bet is to reach out to youtubers with a decent following who are worried about the next banwave. I understand you're trying to do something similiar to thearmchairhistorian.com but for a large audience... but you need the backing of multiple youtubers who already have hundreds of thousands of subs to get off the ground.

Impossible? No. Just really difficult.