Yes, it seems pretty certain the Apple is going to lose this in court, and will be required to break the security on the 5c. But newer hardware with Secure Enclave could be rendered Apple-proof by preventing an update to the Secure Enclave firmware without first unlocking the phone (or still allow a locked upgrade, but wipe all user data when upgrading in that manner). The fact that they haven't said unambiguously that they can't get into newer hardware at all definitely makes it seem like they allow non-destructive updates to SE on a locked device.