[freeflight]

Ease of access to piracy could play a big role. I haven't looked into this for a long time, but last I checked an iPhone needs to be jailbroken to side-load anything not from the AppStore.

While with Android even with most default roms it's just a matter of changing one setting in the options and transferring the pirated apk file to the device to launch it.

A much more straight-forward process with Android devices vs iOS devices and piracy strives on convenience.