Fair question, and we all wonder the same thing. But you have to keep in mind that we might THINK someone is better off than us, when they don't feel that way, so it's all about perception. Happiness is the most important thing and someone who has a lot isn't necessarily happier than someone who doesn't.
Example: my friend spent a few weeks on an island doing charity work, watching kids roll a tyre up and down the road and having the time of their lives doing it, and thinking of us back here in the states with our iPhones, and video games, and she said her boyfriend said to one of the islanders "We feel sorry for you."
He replied "We feel sorry for you! We have a simple life. You have all the distractions of wealth, materialism, technology, etc."
To them, that'd be a terrible way to live, yet we think we're better off.