Android fragmentation was never really about the resolution differences. As stated by the various Nexus 7/10 reviews out there, many Android apps on tablets are

Android fragmentation was never really about the resolution differences. As stated by the various Nexus 7/10 reviews out there, many Android apps on tablets are just badly resized phone UIs, but they're still functional. Badly coded apps might crash at unexpected resolutions, but most decent developers avoid those mistakes. The fragmentation comes from the woeful OS update situation (API fragmentation) and there being a ton of different manufacturers each producing something slightly different (hardware fragmentation). Older iPhones don't support all the features a 5 does (panorama, Siri, etc), but they support the latest APIs. Want to use a ICS TextureView for fast GL rendering to a view? 70% of the userbase won't have support. Writing an image processing app that depends on the GL_OES_texture_float extension on the GPU? Phones from with GPU X will have the extension, phones with GPU Y won't. Need a gyroscope for some fancy UI widget? What about NEON intrinsics? What about an app that relies on all three? Having so many more combinations of hardware is a blessing and a curse, and testing against all the possibilities is a real hassle. Every platform has hardware fragmentation - Android just has it the worst.