If you patch any part of the software stack on an embedded device, and then are dumb enough to apply a vendor software update to the device, you get what's coming to you. Your phone is fine: it's the same bundle of components and ICs and wires and transmitters you got when you forked over $599 for a phone. You decided to take over the software, now you figure out how to make it work after you mangled it.
Doesn't anybody remember Black Sunday? The DirecTV hackers patched the software on the H cards, just like the unlockers did to the iPhone. They got free PPV TV from it. Then, a week before the Super Bowl, DirecTV ("Dave") sent a software update over the public airwaves that burned "GAMEOVER" over the whole H card, permanently. They literally broke the hardware.
Short of not locking their phone to a specific carrier at all, what, exactly, do people expect Apple to do here?