They already are. You can sign in to your Apple ID, nuke your phone from orbit, put it in Lost Mode so that it can't be used for anything other than 911 calls,

They already are. You can sign in to your Apple ID, nuke your phone from orbit, put it in Lost Mode so that it can't be used for anything other than 911 calls, etc etc etc. And you can call your carrier, report it stolen, and bam - the ESN is blacklisted and the phone is a brick.