You are falling for a common pitfall, assuming that intelligence is the dominant factor in success. There is enough evidence to suggest intelligence is a thing and that it does help general ability broadly, but it is basically always dominated by other factors, be it affluence or experience. It's entirely possible for an expert in 1 field to end up being completely clueless and seeming like a dumbass when talking about anything else. There is even research to suggest people that are experts in one domain can be easier to fool into thinking they are more competent in all domains, actually making them less likely to seek external opinions and ending up worse off.