No amount of money is enough. The world richest is still striving hard to make more money notwithstanding that, what he has already made will last him for lifetime.
An economist said "human wants are insatiable", the more money you make the more the need for money arises.
It is a mystery which one can not understand, God made it like that. Provided a man has not yet acquired the whole world, he can't stop struggling for money. The more money the more the need for money.
Therefore nobody had had enough money!