Android may have a bigger install base but they also seem to have a much bigger group of "low power users". These are the people such as my step-dad and some of their friends who bought a cheap Android phone as it was the same price as a old style candy bar or flip Nokia but it had a much bigger screen with adjustable text size (superb for their aging eyes) but they do
nothing on the phone that would be considered "smart". They call and they text. That is it. Whereas I don't know anybody who would buy an iPhone and then not use all the smart phone features. Hell I know at least 6 people (not conclusive but interesting IMHO) who own Android phones but don't even have a Google account so have never download an app or even opened the web browser or maps built in apps.
With the death of the old mobile phones and the rise of the smart phone someone had to pick up the place of the LCD, with the much lower entry level of Android on dirt cheap hardware it is clear that Android has picked up the crowd of "I just want a phone that makes calls" crowd which I can't see Google making any money out of.