It's possible that success isn't determined by something that's normally distributed like intelligence or hours worked. Say the key factor is what they call "grit" or determination. If this occurs according to a power law instead of a normal distribution, you could have a situation where the average person has a score of 0.1 and an all time determined person has a score of 1, or 10 or 100.

We can see easily that no human has an IQ of 10x the average. But determination to accomplish a goal is difficult to measure, empirically or subjectively. I can't really say that super rich person X didn't just want it 10x or 100x more than everyone else.

It's interesting that the authors were able to come up with a simulation that roughly matched real world wealth distribution. But there are a large number of potential factors that they did not and could not account for in a model. I fully agree with the idea that all great wealth comes from luck and chance in some form or another. This article is definitely stating what I believe to be true. But I don't know if they really proved anything.