authorized_keys does not get copied while creating new droplet from a snapshot image. Allow such mechanism
That's specifically not done because it's safer for security to overwrite the keys then assume that a person remembered that the same keys would be available there.
Since you can specify which keys you want to add to a server and the keys have full root access it's safer to have customers specify exactly which keys they want and when rather then assume that what is on a system should be respected.
You won't be notified about changes to this idea.