A brilliant and tenacious person can fail due to bad luck, but you can't succeed at the billionaire level WITHOUT being brilliant and tenacious. So bad luck can

A brilliant and tenacious person can fail due to bad luck, but you can't succeed at the billionaire level WITHOUT being brilliant and tenacious. So bad luck can be a factor, but good luck is not, really. Good luck might separate the billionaires from the millionaires, maybe.