The capitalist economy can function as long as it can find new ways to expand profits. That's the core of capitalism - somebody owns the ability to decide what

The capitalist economy can function as long as it can find new ways to expand profits. That's the core of capitalism - somebody owns the ability to decide what is produced, they use that ownership to choose production that is profitable. If some capital-holder chooses to direct production towards something other than maximizing profit, they end up with less capital than someone who does, and thus less of a say in future decisions, so in the long run production decisions are mostly owned by profit-maximizers. It's mostly worked for us since there's plenty of profit to be had by satisfying human needs and charging for it. But, if people run out of needs or money, then the capitalist system will find some other way to grow, whether or not that involves doing anything helpful to anyone.