Until these OS also start putting forward something like WebOS that tried to get phones back to on open web, there is no breaking the binary format and Appstore monopoly. I wish Europe would have forced that 10 years ago since the US is beyond saving.
What binary format?? Go read facebook's "source code", is that any more open than a random apk? If anything, apks decompile quite well.
Decompiling apps only works if you can get the app. I don't understand GP's problem with the apk format either, but you do need to break terms of service to get the files if you don't have a phone with Google services installed. Whether that's ethical or legal is up for debate