Ummnm,OK. Is earnings the ultimate measure of a musician?
NO, but when they acquire deep pockets they can afford lessons with the best of the best.
Some famous recording artists had chops, but many needed lotsa lessons.
In the '70s, flute lessons with a symphony player was $50/hour.
The fairly accomplishedr student's school paid $25 and the student the other $25.
As a reedman and fingerpicking fretted string player, I took a lesson with a legit flute/piccolo player.
Never played flute as a young Lad.
We got along well and at the end first lesson he said, $50 for others, but what do you charge for sax and string lessons?
$20 per hour but I usually ran more than 1 hour, as necessary.
He said just $20 per hour for you, and put me on his schedule as his last student. We played duets long after each lesson.
Everyone I studied with is long gone,
so if I call for lessons, beware.
Ian Anderson and Herbie Mann got better after lessons and lotsa practice.