The odds of a smart middle class entrepreneur making a successful business are actually way better than making it to the NBA or NFL. To say these are equal odds is misleading.
A successful middleclass business does not equal billions or necessarily even millions, so I fail to see how the gp's comparison is off? What he is saying is that you are as likely to be the next Bill Gates as you are to be the next Michael Jordan, not that you are just as likely to be the next Bob Smith who runs a 40-people tech consultancy shop.