I think it's impossible to seperate the variables of intelligence and wealth in terms of the degree to which they determine success, because the strength of the correlation between ability(a multi-faceted thing) and wealth is tough to assess. There will be at least some correlation between the abilities of parents who got wealthy recently and their offspring, in the case of 'new' money. However, there are different forms of ability, and a sample of rich people, are, obviously, going to be people who are more shrewd in, and more interested in, financial matters-but this may not bear total relation to more 'academic' ability. Also In the case of 'old' money thats been there for generations, there may well be very stupid wealthy people, as the intelligence may have been bred out by then, or as education becomes less valuable at such levels of privelige.