You might be surprised at how many famous professional musicians don't read music notation. Outside of the classical world, session work, and jazz fake-books, it's far from de rigueur.
This is true. I read an interview with Hans Zimmer who has scored dozens of Hollywood films (including Blade Runner 2049) and when he first arrived in London in the 1980s he couldn’t read music. Not sure about now.
ETA: he did eventually learn how to read music:
“I learnt to read music after I bought the Roland MC8 Microcomposer, because it then became essential for me. … I learnt music by ear and have picked up most of my technical knowledge through the sessions and gigs.”
https://www.muzines.co.uk/articles/ronnys-electro-music-caba...
It's one of those "lies programmers believe" kind of things - we like to think that there is one definitive "notation" of a piece of music - but even when there IS accurate sheet music, it only tells part of the story.
Music before recordings was much closer to jam-band style than people realize; and in the Middle Ages you could hear substantial differences in the same song just by traveling a few tens of miles.