Absolutely every aspect of it?
What’s so hard about adding a feature that effectively makes a single-user device multi-user? Which needs the ability to have plausible deniability for the existence of those other users? Which means that significant amounts of otherwise usable space needs to be inaccessibly set aside for those others users on every device—to retain plausible deniability—despite an insignificant fraction of customers using such a feature?
What could be hard about that?
Android phones are multi-user, so if they can do it then Apple should be able to.
Maybe one PIN could cause the device to crash. Devices crash all the time. Maybe the storage is corrupted. It might have even been damaged when it was taken.
This could even be a developer feature accidentally left enabled.
It doesn't seem fundamentally different from a PC having multiple logins that are accessed from different passwords. Hasn't this been a solved problem for decades?
Android has work profiles, so that could be done in Android. iPhone still does not.
iPhone and macOS are basically the same product technically. The reason iPhone is a single user product is UX decisions and business/product philosophy, not technical reasons.
While plausible deniability may be hard to develop, it’s not some particularly arcane thing. The primary reasons against it are the political balancing act Apple has to balance (remember San Bernardino and the trouble the US government tried to create for Apple?). Secondary reasons are cost to develop vs addressable market, but they did introduce Lockdown mode so it’s not unprecedented to improve the security for those particularly sensitive to such issues.
You think iPhones aren’t multi-user for technical reasons? You sure it’s not to sell more phones and iPads? Should we ask Tim “buy your mom an iPhone” Cook?
> despite an insignificant fraction of customers using such a feature?
Isn't that the exact same argument against Lockdown mode? The point isn't that the number of users is small it's that it can significantly help that small set of users, something that Apple clearly does care about.