Why isn't almost everyone on the planet a millionaire?

Over 7 billion people are on the planet. Even if each person worked 40 hours a week, and only earned 10 dollars an hour, they would be making over 20,000 dollars a year. If you assume that they make that 40 hours a week, 52 weeks a year for 50 years, then they would have earned 1,000,000 dollars if they saved all the money they made.<br><br>Edit:<br>Thanks to everyone helping me understand why this isn't the case