Except that isn't true for over-the-air broadcast radio. The musicians and the studio don't actually get a penny from radio play, even sometimes the singer - that is considered promotional. Only the songwriter (they guy or gal that writes the lyrics, if any) gets paid. For many years the studios would be forced to pay money to get airplay, as well (payola).
Furthermore, musicians get screwed by the recording studios, as well. Usually the contract requires ownership rights of a recording to be owned by the studio and not the musician. Even worse, some studios make this a "work for hire,' meaning the rights never transfer back to the original artist (it is corporate owned with a longer copyright). EMI retroactively made their entire catalog works for hire, meaning bands like Pink Floyd are perpetually corporate owned. If you think that is the end of the screwing, nope - all production costs come out of the musician's cut - recording, promotion, packaging, etc. As a musician, you can sell 20000 albums and still owe money, especially if you got an advance. The studio can then go after your gear if you didn't pay back your advance (very easy to do if your band is a business, not so easy if it isn't).
I got out of the business precisely because it is unfair and leeching. I did try my hand at songwriting for a bit, but I got a Software Engineering degree and it was far easier to do that than try to peddle songs.