Yes there are a lot more Android devices sold than iPhone, but the typical Android user doesn't use apps. There is a reason why developers make 4x more profit on iPhone than Android. Many Android users get free 'good enough' phones or get Samsung phones at huge discounts. These users aren't inclined to download and / or buy apps with their device. They generally make phone calls and text. That's ignoring the fact that it's a LOT easier to make a good app on iPhone than Android. Developers prefer the Apple ecosystem because there are fewer devices to support, better tools, etc.
That's actually not true, at least from my perspective as a contract developer. I've been on probably a little over a dozen mobile projects in the last 3-4 years, doing both Android and iOS work. Typically, the Android guy points out his work at the same rate as the iOS guy and the delivery time is the same - whether I'm the Android guy or the iOS guy.
Android's fragmentation makes life difficult for some types of apps, but it's just one in many factors that make up each platform's strengths and weaknesses. Doing battle with the cert requirements and heavier server infrastructure for APN's can create an equal schedule hit on the other side of a few copied layouts to support multiple Android densities.
It's almost certain, however, that iOS users tend to be more affluent. If you walk into a Verizon store with an empty pocket, you will walk out with an Android phone.
As you move "up" the curve into the higher brackets (and Model S owners), I wouldn't be surprised at all to see that those car owners are tilted heavily towards iOS. Even the time tracking software used by my sister's law firm only supports iOS for mobile (in addition to Windows/OSX).
Hopefully, Tesla will catch Android up soon, as the actual expense of keeping an app that simple updated is quite trivial in terms of project work. A UX guy, PM, and a few devs are not a ton of money. Either that or open the API and document it so the community can do the work.