I know. With Android, you can install apps two ways, from Google play or from a .apk file. If you have the .apk file, it doesn't matter if the dev. removes the game from Google play or not, but that's not the case with (C)Apple, thus people selling their phones with Flappy Bird.
nope,
It's called an .ipa file on the iPhone and people are too stupid to know how to do that in general. I've installed apps long after they are dead and gone from the AppStore.