That imagined world,
in which individuals only wanted to invest their money in stocks and not on any other product that has anything less than X% annually
is inconsistent with how people think about investments (and how financial markets work).
The reason is that returns are not static, but respond to demand. If everyone wants to just buy stocks with ...
Yields for those things would go up (lower supply of money increases the price of money).
Yields for stocks would also go up (greater demand for stocks increases the price of stocks) until everyone owns all the stocks they can and then they would be rather low. First person to sell gets to keep it.
One day someone will figure out they can make more money by ...