10 billion divided by 6 million is on average $1666 per developer. They won't publish more statistics like median.
If they did you'd probably find that it's a few bigger developers getting the lions share of the proceeds and most developers making far less.
So for whom is it "good money"? Apple who took their 30% off the top.
Sent from my SCH-I605 using Tapatalk 4 Beta