Elvis was the same way.
There was a time when Willie Nelson and Kris Kristofferson were the go to guys for songwriting that was made famous by others.
At a wedding I met a man who played bass for both Kris Kristofferson and Johnny Cash, plus others as a studio musician in Nashville.
He confirmed the Kristofferson/Cash helicopter story regarding Sunday Morning Coming Down. He corrected my version; Kristofferson after landing in Johnny Cash's back yard, presented the sheet music to June, not Johnny.