Sales per-device is irrelevant, IMO. If I sell 100 for 10 devices, it's better than selling 90 for 3 devices. It's not like I have to add one IF() condition for each new model in my code; merely that I have to plan for slower CPUs and different screen sizes and resolutions, and when I do so, it's for a whole group of similar devices.
However, I have a HTC MyTouch android phone that is still stuck in 1.6 land. I upgraded from 1.5 recently, but it was not the simplest process to do so. HTC doesn't really make it easy for phone owners to upgrade their phone OS. It's possible for me to use the CyanogenMod to upgrade my OS to 2.0, but not without lots of effort at the command line.
The current slew of 1.5/1.6 android devices out there right now will probably never be upgraded to 2.x mostly because the phone manufacturers rarely make it an easy process.
Usage stats from my app in April (somewhat unscientific but illustrates my point decently): iPhone 3G: 49 users iPhone 3GS: 48 users iPod Touch 2nd Gen 4 users iPod Touch 1st Gen 3 users iPhone Edge 2 users iPod touch 1 user iPad 1 user (might have been me...)
That being said, it clearly says that the Android platform is growing.
Would you rather have 100,000 potential users and make 1,000 sales or 200,000 users and make 800. Or maybe make the same amount of sale but being able to charge more because you know that who spend $500 for a phone is more incline to spend $10 on an app than somebody who spent $100?
If the iPhone user buys 3 apps for every 1 the Android user does, but in a couple years there are 10 times as many Android users, where do you sell your app?
The attach rate and the market size make all the difference, and there is no data to support the conclusion you are trying to make.
A gaming PC is a hell of a lot more expensive than a console, yet their attach rate is way way lower than a console.