I’d rather have access to pretty much every song on demand for $4 per month and not own it, than pay per song.
I pay $4.25 per month for Spotify. That’s $51 per year. I have access to pretty much every song, or I could buy 39 songs to own instead.
I save more than 39 songs per month. Financially it makes no sense to buy them. Especially if you consider I get bored of some songs, and never listen to them again.