It would take 2 million copies to sell at 60 for 120 million in sales. While there are plenty of games that easily get 2 million or more sales, it's not the majority.
About the article, it's pretty ridiculous that the president of gamestop would include sales well after release to bring the digital average down to $22 when an important part of their business is selling used games which is basically the physical distribution equivalent to digital sales. Except in gamestop's case, the developers don't get any of that money.