If you have any data on this, can you please link to any? From an iOS user POV, I always buy apps by browsing through the App Store. Starting to learn Chinese? - Download all free Chinese dictionaries and see what sticks. etc...
It's exactly like buying music - I have lots of friends who buy iOS apps, but no two of us have the same taste in apps, so everybody ends up browsing for themselves.
This is a great insight into how people actually search and use apps. It makes the case for free-to-download with in-app purchases. People won't think twice about downloading a free app to try it out, and if they like it, they'll spend the extra couple bucks or so to unlock its full feature set. My guess is that this is more profitable to everyone than Android's "erase in whatever time" to get a refund scheme.
It's exactly like buying music - I have lots of friends who buy iOS apps, but no two of us have the same taste in apps, so everybody ends up browsing for themselves.