Android supports text passwords as well. Also, in a sane security model, it'd be possible to separate having a long password for elevated privileges (i.e. thin

Android supports text passwords as well. Also, in a sane security model, it'd be possible to separate having a long password for elevated privileges (i.e. things that could further open the door to compromises like booting and installing apps) from the one simply to unlock the screen. Your average consumer probably wouldn't avail themselves to such measures, but it'd let the paranoid and companies with security policies at least have semi-reasonable security as an option.