Um, no.
The thing that you're missing is that most models in a given range only differ by their DPI. iPhone 3GS -> iPhone 4 was a simple doubling of resolution in each direction. Update an apps resource file to include extra bitmaps with the same name as the existing ones but with @2x on the end of the name and the system automatically picks the right one for you. The same when it came from moving to the iPad 2 -> iPad 3, just add extra bitmaps. The iPad Mini looks to software like an iPad 2, so no changes there. With the iPhone 5 Apple update the SDK so that it could automatically reflow forms on larger screens. Code had to be updated to use this.
So developers need to write code to support the iPhone (using the reflow) with two sets of bitmaps, plus if they want to support the iPad they need a set of forms designed for that (again with 2 bitmaps for everything). One program, two sets of forms (phone and iPad versions of the app), a maximum of 4 bitmaps for each item on the form (if you can't share the bitmaps between phone and pad) otherwise 2 (low and high DPI).
The problem that Android has is the concept that one size suits all. In practice iOS developers have made significant changes to their forms to make use of the extra screen real-estate. That's where Android is at a disadvantage in the App marketplace - there are only something like 10,000 apps that have been coded for Android to make use of a bigger tablet screen vs 300,000 for the iPad, and many of the gaps are from big-name providers.