yeah i see what you are getting at...i do not think any musician burns out unless he is touring too much but as far as the music inside of a person...it is always there...it is society and the so-called white collars that make or break a particular artist...that is why one week it is cool to play the blues, another week it is the head and body of jazz...then classical rears its technical side...you get the picture...
what i am trying to say is it is a combination of all of us that makes anyone great...if it inspires us, we embrace it...if we do not like it, we trash it...nobody in the late 60's said that jimi was going to change the attitudes of millions of guitar players...most thought he was too loud played out of tune and was too introverted on the stage...today we know that he was one of a very few that mastered the instrument and intriqued many...what if he were alive today???would he have evolved???...would he have burned out??? we will never know...
there will never be another jimi...or a srv...they would be the first to admit that you need to innovate, not imitate.:)