Lofi Girl the company is a music label (formerly ChilledCow). Many of the popular channels are promoters who use their listener numbers to negotiate with small artists.

Curiously, one subversive way to "monetize" something that google won't allow you to while Google runs ads on it is to use music licensed to a label you own then claim the video with your label and capture a portion of ad revenue that Google applied.

Strategies like this are incredible.

However, it looks like the bar for monetizing is raising quickly, requiring a "face" or "original content". However, I've known friends who've been unable to monetize their own clips channels.

How is it subversive? You are letting Google display ads on content which is yours, it seems perfectly legitimate that you should get a cut.