Since the only way to make money is to provide something people want, if you are doing something that provides you with money, you are making your customers' world a better place, at least they must think so.
I promise to take care of toxic waste for some large
manufacturing corporations. I take their money and 'dispose'
of the waste. What if I dispose of the waste into waterways
(lakes, rivers,etc)? My customers are happy because the waste
is taken off of their hands. If anyone ever finds out about
the dumping, they can claim to no know anything (and they
may well not know anything) and *I'm* the one that takes
the fall, not them. In the meantime, they get to reap the
benefits of cheaper disposal (since it's not being disposed
of properly). I would hardly say that I'm making the world
a better place though.
Love your wife and your children. Help out a friend. Clear your elderly neighbor's driveway in the winter. Sure, the effect is tiny, but you've got to start somewhere.
Let's say your customers are "everyone in the world," and your product is diamond rings. Your customers rank each other based on how big of a diamond ring they own. All customers want a bigger ring. When you sell one customer a slightly bigger ring he moves up a rank, and someone else correspondingly moves down a rank. In this abstract model if we assume rank is as important to each participant, you have provided no wealth.
This model corresponds well to bits and pieces of an absolutely massive portion of our economy.
Why does "working on a startup" equate with "making the world a better place?"