If the battery has run down or the phone does not have a good Internet connection at its current location, the phone cannot report information about where it is located. Apple has no control over the battery or the availability of a good Internet signa where the phone might be located.
In this case, the best that Find My can do is show a last known location for the phone. If he battery continues to decline, it is not possible to report another "last known location".
If the phone has a decent battery charge and a good connection to the Internet, it will appear on the Find My map.
If Apple cannot control the battery state on the phone or the availability of a good Internet signal where the phone is located, what are you proposing that Apple can do to improve these things? Showing the same "last known location" when you already know what that was is not going to provide much help.
In any event, if you want to suggest something to Apple, you need to contact them directly.
Feedback - iPhone - Apple
You have posted to a user-to-user site. We are all users here......just like you. Apple is not here.