Success is more than being born with genius or having a lot of luck. No one accomplishes success by themselves. There really is no "self-made man/woman."
Don't forget the enormous amount of work that goes in to what we think of "genius." The Beatles and Mozart put in more than 10,000 hours practicing before they ever got "good."
By looking at examples of "exceptional cases" we can learn lessons about "success." There are certain circumstances around successful people - culture, generation, year/month of birth, cultural background, lucky breaks in their lives, people who are around them, where they are from, etc. You only need to be "smart enough" and the rest is luck and hard work.