Q: Why doesn't iCloud Find My iPhone tell you last known location of device?

Device does not appear in Find My iPhone

This can occur if:

• The date on your device (iPhone, iPad, or iPod Touch) is incorrect. This can be set in Settings > General > Date & Time.
• Your device is not up-to-date. It needs to have iOS 5 or later.
• Your iCloud account is not configured on your device. Enter your iCloud account information in Settings > iCloud.
• You have multiple iCloud accounts entered on your iPhone, iPad, or iPod touch. Only one account can have Find My iPhone turned on at a given time. Log in to Find My iPhone with your other iCloud accounts until your device is listed.
• You have already started an erase of your iPhone, iPad, or iPod touch. The device will not appear on the page until it is reconfigured with your iCloud account information.
• There is scheduled maintenance or another issue affecting Find My iPhone. Check iCloud Support to see if this is the case.
• Your device has lost network connectivity. If you have access to your device, and it appears to have an active Internet connection, enable and then disable Airplane mode. If you continue to have issues, turn the device off and back on.
• Find My Mac can only locate your Mac if it is connected to the Internet via a known Wi-Fi network. If your Mac is connected to the Internet only by an Ethernet cable, Find My Mac will not be able to locate your Mac.

Source

iCloud: Find My iPhone - Support - Apple

This does not answer the question what so ever. Could you please be helpful and answer the question....

How can we get the last know location of a device?

From other apple sources it looks like it should show you the last know location for up to 24 hours. But it does not show this. A device was lost, and it does not show any last know location? Why is this?