Are you serious? Maybe you missed the entire privacy conversation around cloud storage in the last couple of years. Also, with your reasoning, your entire laptop should merely be a client for a remote storage.
Saving stuff locally is good for privacy, for performance, for offline-capabilities. You can back up your entire phone LOCALLY, to have a solution of your stated problems (theft, physical damage).
i am very serious. people lose their devices all the time.
never save important data on a single device. you simply delay the inevitable "i lost my data" scenario.
non-important data on the other hand should have no problems living on a single device. or even localstorage.
and as i said before, i don't think your average user has any ideas about backing up. that's why it almost always comes back to the developers to implement it.
Saving stuff locally is good for privacy, for performance, for offline-capabilities. You can back up your entire phone LOCALLY, to have a solution of your stated problems (theft, physical damage).