[hirundo]

You could get the same distribution if everyone is assigned a random amount of selfishness regardless of wealth, but some people are better at achieving their selfish goals than others, or just luckier. How could someone know that the result is primarily due to non-uniform selfishness?

You could measure selfishness in small experimental scenarios and try to correlate it with the wealth of the subjects. Does that evidence exist?

[wenebego]

I never claimed that.