That "app" advantage will erode quickly. At some point, the numbers become overwhelming enough that you're only doing your own company a disservice by putting Android second.
Apple's profit advantage is also eroding. Samsung is getting ready to announce a $7.3 billion Q3 profit, doubling what they made year-over-year.
I understand the sentiment regarding the backseat that Android app development has taken for the past couple of years... but... I don't think marketshare factors in the decision that much.
Here is my perspective as someone who is having ongoing projects on both Android and iOS... specifically... both the HTC One X and Galaxy S3:
I MUCH prefer working on iOS, not because there is a huge user base willing to buy my apps, or because there is only one device that I have to write for, but because... the hardware on iOS side is of a much higher quality than Android. And by "much higher", I mean... the camera is of more consistent quality, the microphone is of more consistent quality, and sensors (gyroscope, GPS) are of much more consistent quality. HTC One X? Horrible... borderline bad camera. Galaxy S3? Super spotty GPS. If I want to implement any idea that involves either of those devices, then I'd have to make severe compromises on the Android side simply because the hardware isn't up to par.
And yes, that means specs sheets (CPU, RAM, etc...) don't tell the whole story. There are other things in a device that are more important.
But on the topic of hardware... Android's memory and performance behavior is wildly different depending on the phone. Heck, on the Galaxy S3 and One X, the behavior is wildly different for different ROMs. I still can't see how I can make an overly complicated app that will perform consistent. It's always either too slow, laggy, or it's running fast but the background behavior is spotty and unreliable. And by overly complicated, I mean something more than simply scanning a barcode and sending the result to a database.
And last but not least, we can go back to marketshare: while the iPhone is having diminishing marketshare, I don't see diminishing sales for my apps. In fact, even for free apps, I'm earning more on iOS side than on Android side. I think it's not just because iOS users are more willing to pay (I have many free apps), but it might in fact be that iOS users are more willing to use apps. Also if I'm pitching an iOS project to a prospective business looking for a third-party developer, I'd always recommend an iPod Touch rather than an iPhone. Or at most an iPad if they want a bigger screen. And I don't think any marketshare analysis done thus far has included the iPod Touch... but yet it's still a very valid app platform for developers. Until someone can challenge that market, in which I'm sure the iPod Touch captures a perfect 100% and is actually higher than iPhone in raw number, I don't think iOS as a whole ecosystem (iTunes, iPhone, iPod, iPad and soon to come iPad mini) would die for many years to come.
And I actually hope that it doesn't... because I'm enjoying a lot of good revenue on iOS as a developer as opposed to Android. If anything, Android development has become more of an afterthought lately, and I don't think I'm the only developer who is thinking this way.
Also just as an aside for those who are saying the iPhone 5 is an incremental upgrade over the 4S... well, in terms of performance, it's not. It's a very different beast compared to the 4S. It's much faster than the 4S and the iPad 3. It's the most powerful iOS device to date... and that's only because I'm avoiding having to state something along the line of "it's the fastest smartphone on the planet" because I don't want to start another pissing war... But that's just reality. As a developer, I can see many things that I can do on the iPhone 5 that I can't do on any other device. And that's solely due to the faster CPU, not due to anything else.