I think there are lots of easy choices.
Paul MCartney. Think of all the Beatles song you know. Macca wrote about half of them. He wrote about half of them before his 28th birthday. Anyone with that capability is going to find fame one way or another, even with the music industry’s legendary indifference to talent. Stevie Wonder is another in the same category. If you have whatever it takes to churn out ‘Songs In The Key of Life’ then you will be famous.
I know people who have worked with Madonna. They tell me that, whether you like her stuff or not, not only does she have whatever talent she has but she is also very hard-working, very driven and determined, and extremely focused on things being the way she thinks they ought to be.
I don’t know if we’re allowed historical picks, but a good one would be Salvador Dali. Could never be anything but what he was.