How to make $80000 per month on the Apple App Store

At WWDC, Apple reported that they've paid out $70 billion to developers, with 30% of that ($21 billion!) in the last year. That's a huge spike, and surprising to me because it didn't seem like my friends and I were spending more on apps last year. But that's anecdotal, so I wondered: where are these revenues coming from? I opened App Store to browse the top grossing apps.The controlled, walled garden at work.