Again more conjecture, but maybe IQ has more to do with concentration and abstract thinking. If there were a relationship between wealth and childhood trauma/stress that could impair abstract thinking, it would make a good case for policies designed to prevent childhood trauma, in particular those brought on by poverty.
Finally, the causal relationship you have set up between intelligence and quality of living situation, while undoubtedly true to _some_ extent, ignores everything we know about system racism, system sexism, our horrific healthcare system and a host of other factors that complicate this idea - at least in the US.
> Income, yes, but not wealth.
Why is that? Wealth is just an accumulation of income.
To be wealthy, you just need to have assets and not do dumb things. Wealthy people either inherited it or had a liquidity event. Nobody gets rich via income. There is some intelligence involved in the liquidity part, but also alot of luck. If you have inherited property in NYC in the last 40 years and didn't sell it, you are wealthy. If you operate a McDonald's franchise, you are wealthy, and probably are of average intelligence.
85% of American millionaires are self-made (i.e. first generation).
"The Millionaire Next Door" https://www.amazon.com/Millionaire-Next-Door-Surprising-Amer...
You can choose to read the book and determine how it is done, and what you can choose to do to become a millionaire yourself, or you can choose to remain a victim of fate. Your choice.