Why aren’t all smart people wealthy?

Smart people may just be book smart but not street smart/financially smart. They also tend to go the more traditional route... get a degree, get a good job and work till retirement, lacking the creativity/entrepreneurship mindset

That's because the smart work for the wealthy, making the wealthy rich.

Not all smart people care about being rich, they could make the world better for the greater good or a meaningful cause.

Smart people may have high Intelligence Quotient (IQ) but they may not have high Financial Quotient (FQ), meaning to say that they may not be good in managing their own finances and tend to overspend. Hence, that is probably why they are not wealthy. Just my humble opinion.