Spotify chill-hop/"music to study to" playlists are popular and people listen to them repeatedly and for long stretches of time which makes them lucrative for streaming revenue.

I know someone who runs a chill-hop "record label". Their most popular songs get on big spotify chill-hop playlists and have ~10 million spotify streams. This equates to around $50-70k USD. Most of their releases have a fraction of this but it is worth it for the odd hit.

My guess is they give artists exposure in exchange for a share of the profits through their channels. I don't know if they can monetize the free stream on YouTube, but they also stream on payable streaming services and sell albums on Bandcamp.

They do sell merch, although I don't know how much that's likely to bring in