Re: Having a distribution monopoly...
http://www.guardian.co.uk/technology/appsblog/2011/nov/22/android-paid-apps-revenues
The figures thus far seem to back up the idea that iOS users are far more likely to buy apps.. It would seem that between 2008 and 2011 (both app stores launched at roughly the same time), the iOS app store made over ten times the money made by the Android app store.
I think the problem Android has actually has nothing to do with the OS itself, but more that a lot of people get Android phones for free, and aren't necessarily interested in it's apps. Where they are interested in the apps, they expect them to be free, after all, they paid nothing for the phone. In essence, they have been conditioned to expect free stuff. Google claim 800 million activations a day, but I'd be interested to see how many of those users actually use the "smart" aspect of their smartphone, and aren't just using it for calls.
iOS is different. The only iOS device you can get for "free" is the iPhone, and that is only "free" if you pay a ridiculous amount of money on line rental each month (>£70 on average), so right from the start, the iOS user is conditioned to pay for stuff.
While what you say about a product being worth what people are willing to pay for it is true, by and large, it's wroth remembering that over the years, there have been several surveys comparing the Android and iOS App Stores, and they have all come to the same conclusion. That iOS users are more likely to pay for an app than Android users.