An a simple example, I can recompile my application and target any device while using 100% of all CPU features in all Android generations. For one application.

An a simple example, I can recompile my application and target any device while using 100% of all CPU features in all Android generations. For one application. And again, your binaries will be very fat if you want to optimize for every possible CPU generation. Whereas Dalvik and ART are stuck to the versions that were burned into the silicon. Which is a problem with how Android updates are distributed, not the principle of doing AOT compilation on byte code. I think pretty much everyone agrees that the push of updates to Android devices sucks, compared to iOS or, to some extend, Windows Phone. Also, for optimization for a particular CPU it should not matter if ART is not upgraded, as long ART was optimized for the CPU at the time the phone was released. (Of course, you would miss out on newer optimizations in ART.)