The thing is running a marathon isn't that hard and there's little to no luck involved. By following a rigid plan most people can do it in about a year. Million

The thing is running a marathon isn't that hard and there's little to no luck involved. By following a rigid plan most people can do it in about a year. Millions of people do it every year. However if you followed all of Sam's advice to the letter you could remain relatively unsuccessful despite all that advice. That's what survivorship bias is about: there's a significant luck component to success.