Why they so successful

These people are different in a lot of ways. Some of them are men and some are women. They come from diffrent interests and they have diffrent professions.
But there's one thing that have in common — they are all extremely successful and at the top of their professions.
An intresting question is: why are they so successful? A lot of people think that the answer is talent — a special ability to do something very well. byt perhaps this is not the answer. Some of these people are not unusully talented. They're good at what they do, of course, but they arent's always excellent. Also, there are lots of people who have talent but who don't become very successful.
So if answer to the question isn't talent, what is the answer?