Mostly luck? No. Though luck is needed.
I suggest reading
Basically the formula is "talent, 10,000 hours of work a little luck to allow you to work for about 10,000 hours on something An idea that's... well good."
As for people like Michael Jordan. There were MANY more people with better genes then Michael Jordan. There are TONS of atheletic freaks who can't make it to the pros.
Michael Jordan became the "Greatest of all Time" because Michael Jordan is an anti-social dick who feels the need to destroy everybody at everything.
If he loses a game of Stratego to his kid he's pissed off for weeks playing Stratego.
When he loses at poker, he forces his friends to keep playing with him until he wins. Michael Jordan is not... lucky.
Just look at his Hall of Fame speech, where he seemed offended that he was inducted more then anything because he believes he still could kick everyones ass. Rich or not, I kinda pity him.
Lots of atheletes are like that, super competeitive combined with a complete loss of childhood... and if your in the NFL shortening of your life by 10 years.
Most proffesional atheletes I do not envy.
