He's not even a Billionare in terms of his personal wealth, which is what Bill Gates, Warren Buffet, Oprah, Trump, etc.... are. It's his worth to the U.S. economy over his career, which then $10 billion doesn't seem like alot when you look at the scope of what he has accomplished. He single handedly made the NBA relevant again compared to NFL and some of the other major sports. He's starred in big movies and definately impacted the clothing and sports equipment industy and sold hell of alot of Mc'ds and Gatorade for them.
Frankly $10 billion isn't all that impressive for it being Michael Jordan!