> Take it from the rich people who have primarily hoarded all that money

That's not how any of this works. Rich people generally have much less of their assets as cash or cash-equivalent than poor people. They also in general have much more debt than poor people, both in absolute values and as proportion of their net worth. (Simply because they are able to take more debt, and with the neverending low interest rates, taking more debt and investing it is basically free money.)