Yes, if the device is powered off then find my phone won't work. Ever hear of a battery dying out? That would turn the phone off also. It's not apple's faiult your phone was stolen. Up until a few years ago find my phone didn't even exist. And many people today don't even activate it if you can believe that.
Sorry for your loss.
Its not Aplle's fault - its mine. But all I'm suggesting is a feature that allows you to turn off 'power off' while the phone is locked. The reason I have a pin to unlock the phone is so that only I can operate it! Just like I can turn off Siri as Finch suggests, I'd like the option to turn off powering off. At least I'll have until my battery dies to use Find my phone!
This subject is discussed fairly frequently. Find my iPhone is not useful unless a particularly ignorant thief takes it. It's primary use is to find lost phones, not stolen. Requiring a passcode to turn it off eliminates one way a thief can disable Find my iPhone, but it isn't the only one, and probably isn't the one used by most professional thieves. Among other ways to disable Find my iPhone:
- Remove the SIM
- Wrap in aluminum foil
- Drop in a shoplifter's bag or backpack with its Faraday shield (copper mesh or foil lining)
- Restore the phone from DFU mode
The Activation Lock feature, which prevents a stolen phone from ever being used again, except by the rightful owner, is the more valuable deterrent against theft. Once word gets around that a stolen iPhone is useless the market value of stolen phones will drop precipitously, and thieves will switch to stealing Android phones.