No time to go into depth, and probably won't do it justice, but a good summary would be "Institutions matter". Like it or not, the kind of negative entropy found in the west isn't easy to come by, and trying to build it from nothing most times will fail in strange ways.
Health insurance is the THE number 1 worry people have. I know a few really smart people who would be out there creating companies and jobs, _except_ for the fact that they are married, with little kids (and spouses that don't work).
This lack of health insurance is probably stifling entrepreneurship more than anything else. People mention the tax code, the 'red tape', etc., but let me tell you; the USA is way ahead of other countries in making it easy to start companies. Where it lacks is in the health insurance area.
I highly recommend Hernando DeSoto's "The Mystery of Capital" http://www.amazon.com/Mystery-Capital-Capitalism-Triumphs-Ev... to get a glimpse of how hard it is to start a business in some other countries.