Yes, I agree it is important and it is still also one of the last things you should think about. Certainly breaking the one-package-runs-everywhere by deliverin

Yes, I agree it is important and it is still also one of the last things you should think about. Certainly breaking the one-package-runs-everywhere by delivering different packages for different architectures in order to save disk space is one of the last things that should be considered. There are plenty of optimizations before this that you can make by compiling your native libraries differently, removing redundant information in resources, etc, before you should consider delivering architecture-specific APKs. And this is precisely because there are many back-channels for distributing APKs (back-channels which are also probably more commonly used in developing economies where those newer phones are unaffordable) in addition to the Play store.