This is a good example of how Martingale can fail spectacularly. Originally, he only bet 5 satoshis - an insignificant sum. He risked 40,000 satoshis to make just 5 satoshis. Doing it once or twice is relatively risk-free. But you can't become rich by making 5 or 10 satoshis. Or even 50 satoshis for that matter. In order to make a good sum of money, you need to do this hundreds, perhaps even thousands of times.
As you make bet after bet after bet, you start to see the chains emerge. Slowly at first. Perhaps a string of three or four bad rolls. Then five... Then six... The panic escalates, until the green digits that you've been waiting for reemerge. Then it subsides. You recuperate, and start betting again.
But eventually it happens. It always happens. Yet another string of bad rolls, not too different from the last few. Six... Seven... Oh no. Perhaps this is the big one? Eight... Argh! Nine... You're down to your last roll. One last shot. Will it be green? Yes? Yes? ...No. It's red. And your whole balance is wiped away.