AFAIK, the illegal part is not the downloading, but the act of uploading/seeding the assets.
But this pipeline you establish - of people "pirating" music and then purchasing that same music later on - was a very common one, and remains so to this day.
Before digital audio was a thing, people would routinely record songs onto tape while listening to the radio. They would then play this music in other contexts, to which they had no license, effectively making these individuals "pirates." Any "pirate" who recorded a Todd Rundgren song in 1972 from the radio, and then purchased his full double-LP "Something/Anything" at Sears the next week, was definitely a win for the artist, the record label, and the industry as a whole.
On top of this, also don't forget that even to this day, consumers commonly purchase the same music when it gets released on a newer audio distribution format (vinyl -> 8-track -> cassette -> CD -> iTunes -> Spotify/Apple Music). "Piracy" now does commonly mean a "purchase" later.
But this pipeline you establish - of people "pirating" music and then purchasing that same music later on - was a very common one, and remains so to this day.
Before digital audio was a thing, people would routinely record songs onto tape while listening to the radio. They would then play this music in other contexts, to which they had no license, effectively making these individuals "pirates." Any "pirate" who recorded a Todd Rundgren song in 1972 from the radio, and then purchased his full double-LP "Something/Anything" at Sears the next week, was definitely a win for the artist, the record label, and the industry as a whole.
On top of this, also don't forget that even to this day, consumers commonly purchase the same music when it gets released on a newer audio distribution format (vinyl -> 8-track -> cassette -> CD -> iTunes -> Spotify/Apple Music). "Piracy" now does commonly mean a "purchase" later.