Only if you measure success in money. Saying personal insecurity and good impulse control are traits of successful people, success defined by money, is like saying overeating is a trait of overweight people. Of course someone insecure/unsatisfied who does not overindulge themselves is likely to end up with more money. But if you were to measure success in, piece of mind, happiness, positivity, maybe the insecurity makes that more unlikely. We tend to only define success in having money however since it's so critical to have more stuff. If you're talking achievements or non monetary rewards, I'd expect insecurity. It fuels the person. Otherwise they would just live a common life it would be enough for them.