[OfSanguineFire]

In the jazz world it is fairly common for pianists to be unable to read music. For example, Colin Vallon, one of the most successful jazz pianists of the new millennium, has admitted in a number of interviews that he never learned.

[rwhyan]

I wouldn't call it "fairly common."

There are certainly outliers who play by ear or rely on improvisation, but musicians in all genres rely on sheet music to develop their craft.

[Rochus]

Many, many "outliers".