It's weird that you think music has only recently become a commodity. Pop music -- because let's be clear, we're talking about pop music, which is any form of music that was written, performed, recorded, and sold in exchange for money -- has been a commodity since the invention of sheet music.

Why are songs canonically under four minutes long? Because 130 years ago, that's how much music you could fit on one side of a 78-rpm disc.

Pop music has always been a commodity. That doesn't mean it can't also be art.

(Hint: Shakespeare got paid too.)