Nicholas Weaver, for Lawfare:

The same logic behind what the FBI seeks could just as easily apply to a mandate forcing Microsoft, Google, Apple, and others to push malicious code to a device through automatic updates.

And:

Perhaps the greatest innovation in computer security in the past 15 years are automatic updates. It is automatic updates that protect the overall ecosystem, and anything which makes automatic updates untrustworthy would prove a boon to attackers.

Trust is a core issue here. We trust Apple with our data. Apple’s stance on privacy shows they get this and value our trust. If Apple caves here, the trust is broken, with far reaching implications. Imagine a scenario where you weren’t sure what entity was on the other side of that automatic update.