Excellence means being better tomorrow than you were yesterday. Success means exceeding the achievements of other people. Excellence means matching your practice with your potential. They achieve it. They do not achieve it unwittingly by 'doing what comes naturally' and they don't stumble into it in the course of amusing themselves.
All excellence involves discipline and tenacity of purpose.
The society which scorns excellence in plumbing because plumbing is a humble activity and tolerates shoddiness in philosophy because it is an exalted activity will have neither good plumbing nor good philosophy. Neither its pipes nor its theories will hold water.