Starting a business in the United States is a little like pulling your own teeth while getting your fingernails trimmed with a wood chipper. The fact that it still ranks fourth overall just indicates how much worse most of the rest of the world is. It's amazing to me that so many nations (the US included) seem to want it to be so difficult for people to succeed in business.
to be honest, it ranks 8th in actually starting a business. The 4th ranking is the overall doing business ranking, which takes other factors into account.
Still . . . that's within 5% of the top of the list, which is shocking given the obstacles to entrepreneurship in the US.