That's the Martingale System (http://en.wikipedia.org/wiki/Martingale_system http://en.wikipedia.org/wiki/Martingale_system), and it fails because no one has an

That's the Martingale System (http://en.wikipedia.org/wiki/Martingale_system http://en.wikipedia.org/wiki/Martingale_system), and it fails because no one has an unlimited supply of capital. Lose 20 times in a row and you've lost $2,097,151 since your last win. And you will eventually lose 20 times in a row. Since you're only winning $1 every time you win, you'll have to play many times to win any significant amount of money.