http://www.apple.com/pr/library/2009/10/19results.html
In the first month of the App Store, (arguably not very close to now, but still) Apple sold about $30M in apps, of which it takes only a 30% cut. The difference between hardware and software sales is a few orders of magnitude.
http://online.wsj.com/article/SB121842341491928977.html
They'd need to sell $3.2B on the App Store each month to match the hardware profit figures.