Well, there is more money to be made in the US than in other countries, but people in other countries are content with less money than Americans. I guess it depends what you mean by make it. If you mean "become obscenely wealthy" then I would definetley agree with you. If you mean, "be comfortable enough to provide for your family", I think a place like Norway may be better, since worker's have all kinds of rights. In Europe, lay offs are much less common. In the US, you think you are doing great, then your company lays off 10,000 people, and you find yourself as an unhirable 45 year old with huge bills to pay.
I would also add luck, ingenuity, and being a cold-hearted backstabber to the hard-work and perserverance mix.