It's more complicated than that. Artists benefit greatly from repeat customers, so it's to their (and their label's) advantage to expose as many people as possible to their product. This will help drive future profits through the sale of albums, merch, and concert tickets. Movie studios are dealing with a much different dynamic.

Artists barely make money off of Spotify anyway. It's just marginally more than they'd get out of piracy, and a more legitimate platform to advertise their content. Making money in music has been all about concerts and merch for a while.

I think think you're making a distinction where there isn't one. For example, you can license music to TV shows, political campaigns, commercials, movies, and video games. Radio stations must pay royalties for playing songs. There are plenty of revenue streams for music outside of "selling it digitally or physically" and a subscription service.

How many songs actually get licensed for movies and tv shows out of the millions of songs that are on Spotify? Political campaigns do not have to have a license to use music. Artists have been complaining about political parties using their music forever.

Radio stations have to pay royalties to the songwriters and musicians but not the singers.

No matter how bad or unpopular a movie is, a studio will always make some money on a theatrically released movie, with each of the distribution mechanisms.