Ricky Skaggs achieved it in the early '80s. Bill Monroe continues to be an active player in the Bluegrass arena. One must also keep in mind that Bill Monore didn't set out to create a new musical form. He started playing his form of music so that he could be himself. No, or he wouldn't be with us today.
Some artists are able to at least achieve that middle ground somewhere.
That gray area between great success and just getting by. The Seldom Scene is a prime example. They have achieved their place in the Bluegrass scene by performances and a sound which are consistent and maintain a quality presentation. The Seldom Scene may however, be no more. Their current plans are to dissolve the existing band at the end of this year.