If someone has changing the world as their primary goal, and they decide that a startup is the best path toward that goal, I don't really understand why they shouldn't do that? To me a startup is an amoral vehicle for achieving its founder's ends, so if they want to have changing the world as priority number one, and are satisfied with just breaking even, that is up to them (and similarly if turning a profit is top priority).

Of course if it doesn't at least break even eventually, a startup is not really a useful tool for achieving anything.