If you look into folk music traditions, one recurring theme you'll find is it's generally not clear who wrote a tune or lyrics, and multiple songs often use the same tune. That's the natural state of music, and the current system of so-called intellectual property is an aberration.
We don't know who wrote "Rolling Down to Old Maui" or "Drunken Sailor," other than that they were popular in the 19th century. They both share tunes with other songs that predate them, just like how there are multiple songs that use the same tune as "The Wearing of the Green." Countless people have performed and rearranged them, and the world only benefits from it.
Everything in art is inherently memetic, building upon the work of others and evolving.
I think it was Pete Seeger who said that the greatest compliment he ever received was someone saying "Oh you wrote that song? I thought it was just.. there".
We don't know who wrote "Rolling Down to Old Maui" or "Drunken Sailor," other than that they were popular in the 19th century. They both share tunes with other songs that predate them, just like how there are multiple songs that use the same tune as "The Wearing of the Green." Countless people have performed and rearranged them, and the world only benefits from it.
Everything in art is inherently memetic, building upon the work of others and evolving.