If anything, the sales distribution he shows is significantly flatter than a normal Zipf ("long-tail" or "scale-free" or "80/20") distribution, as you would expect in a free market; app #1 should sell 50× as much as app #50, not merely 10–20× as much, and 100× as much as app #100, not merely 30–50×. It's great that unknown developers can get free marketing by making it to the App Store's top 50 list. Maybe that's why the distribution is flatter than you'd expect?