How can Apple make progress on people making their phones easy to steal and easily guessed passcodes that allow accounts to get hijacked? Those are user responsibilities not Apple
Of course they CAN. For example, there has already been the suggestion to add screen time passcode to prevent account changes even if the thief knows the lock screen passcode. But this is not the intended use of the screen time code and Apple can make a proper way to do it.
Obviously, both users and Apple understand the need to add a layer of protection AFTER the device has been unlocked. For example, there are hidden albums in photos, locked notes, etc. In iOS 17 Apple is adding Face ID protection for private browsing. Why would you need all these things if there is a lock screen passcode?
Because although it is your responsibility, there is a possibility that someone can get access to your phone while it is unlocked, and this is to protect the data that you care most about. So of course it is the user's responsibility, but Apple CAN add protection. And they are already doing it. I am just saying that they should add this kind of protection also to the Apple ID sign in on the device and other crucial areas.
If you are walking on the street looking at Google Maps with your phone unlocked, and suddenly a gang of 200 people surround you and one of them snatches your phone. Yes, it is your responsibility to subdue all 200 of them and get your phone back, and as responsible as your sound that's probably exactly what you will do, but wouldn't it be nice to know that you have extra protection on your most important data and your account even though they took your phone while it is unlocked?
Otherwise, you can also say that it is the user's responsibility to guard their device (which it is), so Apple should/can not even add a passcode on the lock screen. User responsibility and Apple adding security features are not mutually exclusive.