It does seem likely that most smart people aren't optimising for wealth. I know a lot of smart people who spend their entire income, and it is just difficult for someone to be wealthy and spend all their income at the same time. Wealth requires surplus.

But even for smart people trying to optimise their wealth - it isn't at all clear that smartness is something to be rewarded. A reasonably competent, hardworking small business owner can be quite wealthy. I would expect them to be of above average intelligence. But I've basically never paid someone because they are intelligent, so it isn't obvious why the market would save the best reward for them.

If I was hiring a tutor I wouldn't necessarily hire the most intelligent person I know. There are a lot of factors to consider.