If you make 30 million people's lives just a tad bit easier, then yes, you've changed the world. If you've caused other companies to take note and copy your business strategy/idea and THEY make people's lives easier, then yes you've changed the world.
Yes, he's rich, but I think he's saying that was a side effect of purer motivations. If you're in it to be rich, then you're in it for the wrong reasons. If you're in it create an amazing product and be impactful on a stranger's life, then you're in it for the right reasons.
Just my take. Could be wrong.