I make a hell of a lot more than $5,000 per year on the Apps I've written. All of them are 100% free, with zero advertising.
Think about that for a second before doing some useless math like dividing revenue by the total number of Apps and concluding most developers don't make money.
No ads and free. So… you sell users' personal info for cash?
Anyway, the App Store revenue doesn't include ads from AdMob and such, so that already is a flaw.