I thought I did.
No, that tells me nothing about why the "AppStore is a money printing machine".
In fact, it has been shown many times to not be a money printing machine, but for a few lucky developpers or the big names that already have a license to print money (EA, Ubisoft, Gameloft...).
It's also not a money printing machine for Apple, representing less than 10% of their profits/revenues when combined with the Music store/Film store/TV store.