You'll notice they are very strict about background processing in applications and the usage of battery draining things such as GPS or cellular data. This helps battery life significantly. Google didn't start prioritizing view smoothness and efficiency until android 3 or 4.
The OS & apps are pretty much pure C from the ground up, with an objective-c application layer. The entire view system (Core Animation) is GPU accelerated with OpenGL from day one.
Objective-C on iOS does not have a GC, so apps are generally faster and more responsive with manual memory management. Many apps can drop into pure C or C++ to improve performance easily.
All of these performance choices give you a faster phone for less processor.
A slower processor also tends to use less energy too. Battery size is a pure weight/size vs capacity tradeoff.
The OS & apps are pretty much pure C from the ground up, with an objective-c application layer. The entire view system (Core Animation) is GPU accelerated with OpenGL from day one.
Objective-C on iOS does not have a GC, so apps are generally faster and more responsive with manual memory management. Many apps can drop into pure C or C++ to improve performance easily.
All of these performance choices give you a faster phone for less processor.
A slower processor also tends to use less energy too. Battery size is a pure weight/size vs capacity tradeoff.