So again we see that apple has been good at getting the platform profitable here is a great article that breaks this down. It ends up being less about the fact that iphone apps are better per say (which I think they often are) but more about the fact that significantly more apps for android start out free.

http://blogs.wsj.com/digits/2013/03/11/the-surprising-number...

but your statement about usage is wrong see the following article on app use:

http://www.cnet.com/news/most-iphone-applications-gathering-...