The math does seem to stack up. The problem is distribution, not total wealth it seems
Edit: Ok this is skewed as US stock markets are really a global stock market, but if you took for example global GDP (~115 Trn) and divided by 8 bn people or 4 person households you end up with 60k per household globally.
Here's a trick I was explaining to my son earlier. We really do live in the Matrix. An announcement comes on and they are resetting - everyone gets a new life starting tomorrow - but randomly allocated over the 8 billion possible "players". We can keep the current social order or we can design a new one.
Do you hope the 8 billion sided dice rolls in your favour and you land in Jeff Bezos body? Or do you think maybe we should redesign society ?