I agree that it would be upsetting if precedent was made, but I believe it
is technically feasible to build a device whose keys are only known by an end user. The FBI is basically asking to go down legitimate update channels to brute force their pass-code, and while that's still a feasible option, of course the FBI is going to ask to use it. Updating the security model of the secure enclave to either destroy keys on flash or disable the flashing mechanism all-together would render the ability outside of even apple's reach, then it goes back down to a question of if you can be compelled to give up your encryption pass-phrase, which I believe precedent has already been set on (please correct me if I'm wrong).
As an aside it bugs me to a fairly large degree that we still attempt to apply very old laws to something they were never designed to address the things we put in front of it. It feels very akin to trying to jam a square peg in a round hole.
Ever play with a wifi pineapple? Ever build one yourself? Congrats! You broke a federal wiretapping statute!
https://www.law.cornell.edu/uscode/text/18/2511
https://www.law.cornell.edu/uscode/text/18/2512