And why would it matter? Even if the capability to create a magic key that unlocked a specific phone remained entirely within a company's hands for future use, why wouldn't the courts just continue to ask them to use it? It's not like the victims of all sorts of other crimes don't have similar don't similarly deserve justice.
Law enforcement at the time was even admitting (which we'd later find out to be correct) that there likely was nothing of value on the phone. It seems fairly obvious that the FBI was trying to use a high profile case to force a paradigm shift. Perhaps we can argue it'd be a good and just one, but arguing that they weren't seems not right.
Instead I am only aware from what has been published that there is the so-called "Secure Enclave" chip in the iPhone hardware manifest that will only give up its secrets to a biometric match, or a user password. That would seem to leave Apple's hands tied?