I've just read an interesting article that's based on a study.
The team has developed a simulation that represents our current situation of rich vs poor people.
Link: https://www.technologyreview.com/s/610395/if-youre-so-smart-why-arent-you-rich-turns-out-its-just-chance/
In a nutshell their model reveals that there is no/little correlation between IQ and wealth.
This reminded me of what people call the "law of averages" -- meaning if you try something more often, then you'll win more often. I think it also means that we should be brave and have the courage to try things again and again -- even if we fail, try it again with even more enthusiasm:
So keep grinding, and one day luck may strike you.
Cheers!
Edit: it is true that many wealthy people are pretty smart, but often times not the smartest within that organization.
It could be that the higher your IQ, the more you start overthinking stuff and the more risk averse you become. While people of lesser IQ posses other skills (e.g. charisma, verbal skills, looks, ...) that are more rewarding in a capitalistic world.