Garreth, you’re absolutely right in pointing out that luck plays a heavy role in determining a person’s professional success or failure. I would also add, though, that luck generally happens to those who are in a position to recognize an opportunity when they see it, and who know how to benefit from it. To do that, a person generally has to be 1) prepared and 2) in the game to begin with.
This was the case in all three cases you cite. Terri Holton was a skilled and well-practiced flea market hunter, Louie CK a stand-up comedian with years of practice and experience behind him, Beane an equally experienced coach. They were working hard to attain their goals at the time their “lucky” break occurred. And they knew what they were looking at when it came onto their radars.
Bottom line: don’t expect a lucky break to fall from the sky and hit you squarely on the head just by walking down the street. You’ve got to earn them.