Good point on the $99/year. Still, good luck convincing Wal-Mart to let you user their stores as a distribution point for your free stuff for a low annual payment.

Apple is big enough that billions can easily be insignificant. According to that article, they've paid out $15 billion total to developers. That means that Apple's cut has been about $6.5 billion. That's over a period of eight years, so somewhat less than $1 billion in revenue per year. Currently Apple is making $10-20 billion per quarter in profit, with yearly revenues beyond $200 billion.