Grace, this is imo a very difficult question to answer. There are a multitude of differences that can converge on success. And even the term success is a subjective one, and only the person themselves can determine if they are a success.
People would think that Albert Einstein the genius scientist was a success, but he died without ever finishing his Grand Unification Theory. Tesla was a brilliant scientist that was more brilliant than Thomas Edison, but he died in poverty. Thomas Edison stole a lot of his work, but we think Edison was a success.
Each person leads three lives, personal, professional, and family. Success would be construed as a Trifecta. but one only has to look at Warren Buffet to know he thinks very little of family.
True success imo, requires that you be able to handle Success once you achieve it and that based on history is very difficult to maintain.
There are many facets of success, and of course most of us think of fame and fortune as success. But that is probably because most of us won't achieve either in our lifetime. And many won't even personally know anyone that has reached it.
But if that was the true measure of success, many people that have achieved either of both have become drug addicts, and were suicidal. Think Hollywood and entertainment stars. The five time graduates of the Betty Ford Clinic are they successful or just persistent.
Looking at the positive side of success, the successful person wants to succeed, and many times above all of else. But the successful few are not always on top because they are the most talented, the most intelligent or even the most gifted.
The simple answer might be Luck, who was helping them, and timing would account for the most successful people.Out of them, are the truly special and unique people that saw a vision and went all in for it.
People like Henry Ford, Andrew Carnegie, the Rockefellers, Kennedys, while people like Bill Gates simply took advantage of a gap in the competition. Gates didn't invent the computer, or DOS or even Windows. He bought and copied from existing technology. Is Microsoft the best, hardly, it is just the biggest. The same is true of entertainers like Cher, Lady Gaga and others.
At the same time, athletes like Jackie Robinson, Babe Ruth, and other legends were truly gifted, and talented and used their opportunity and became successful in sports. But could they measure their life as a success. Mickey Mantle the center fielder for the World Series winning NY Yankees was at the top of the field, yet he died from alcoholism.
So after all of these words, I am no closer to really answering your question. But I thought I would at least try.