In one line of reasoning, money is a proxy for happiness (I'd rather change this to value... but this doesn't matter because this example is so distilled). So, companies exist to make people happy. This works by providing a good or service that makes a customer happy in exchange for money, which the company can then use to give to employees and shareholders so they can be happy too. Since the company creates a profit, happiness generation can be sustained for multiple parties well into the future.