iOS app success is pretty much guaranteed - if you're smart enough to take your skills and start selling them at market rate to every Tom, Dick, and Harry who wants to hit the iOS lottery.
In a gold rush, the guys who do the best are the ones selling picks.
I have two iPad music apps in the store that both had long stints in the "what's hot" section and one was as high as #13 in the US music category and #7 in the UK.
When I consider how much time they took to write I would have been much, much better off spending that time on oDesk contracts at $20/hr, and don't even talk about what I could have made on a real developers salary in that time.
Selling your own apps now is a fool's game. Apple trumpets the successes because it helps them sell hardware.
Hard to say. As other people have reported, total profit seems to be loosely correlated with price. I sell more at lower price points but total revenue is similar.
Some music apps make do really well but they're generally much less complex and technical than mine.
In a gold rush, the guys who do the best are the ones selling picks.