They're presumably already 99% of the way there. If the Secure Enclave can be updated on a locked phone, all they need to do is stop allowing that, right?
To me, the more profound consideration is this: if you use a strong alphanumeric password to unlock your phone, there is nothing Apple has been able to do for many years to unlock your phone. The AES-XTS key that protects data on the device is derived from your passcode, via PBKDF2. These devices were already fenced off from the DOJ, as long as their operators were savvy about opsec.
To me, the more profound consideration is this: if you use a strong alphanumeric password to unlock your phone, there is nothing Apple has been able to do for many years to unlock your phone. The AES-XTS key that protects data on the device is derived from your passcode, via PBKDF2. These devices were already fenced off from the DOJ, as long as their operators were savvy about opsec.