I have to disagree. Lots of people who play other people's music also play their own. Also, how do you count jazz players, who often don't write the songs, but take extended improvised solos over the chord progressions? I definitely learn music written by others note for note, i'm big into transcribing solos (transcribing = writing down, not just learning) and learning classical pieces. When playing jazz (or rock, or blues, or any other non classical style,) however, I improvise all my solos. I'm not sure where I'd fit....