it seem most of the service are not been used to there true capacity.
Find my iPhone isn't designed to locate stolen phones. It is designed to locate lost phones.
The difference between lost and stolen, is if the phone is stolen, the thief will do everything he can to avoid being found. So, he will turn the phone off, wipe it, not connect it to the internet, turn Location Services off etc. to prevent "Find my iPhone" from working.
If a phone is just lost, there is a much higher chance that "Find my iPhone" can do its job. Most honest people would try to return the phone to its owner and not turn it off, or they would hand it in to the police.