No, I think I quite understand their world changing impact, but those are two examples of the very few companies that have reached the sort of scale where they

No, I think I quite understand their world changing impact, but those are two examples of the very few companies that have reached the sort of scale where they actually change the world. They represent the vast minority of successful startups, which are a vast minority of all startups. In any case, what is changing the world if not helping people? Or, as I phrased it in the post, improving the circumstance of mankind? There are plenty of ways to do it, and it need not be charity (marine biology or journalism, the other examples from the post, are not charity) and it need not be altogether altruistic in purpose, but to change the world in a desirable way necessarily means helping people. For example, Google helps me find information. Facebook helps me stay connected with friends and family.