Re: Why is this even necessary?
"Basically if you take anything out of the device then it no longer has its necessary relationship with other components in the phone. "
It's called TPM. It can still be faked, with a hell of a lot of effort. As the FBI works routinely on national security matters with the NSA, it's likely a filling in a few minor blanks operation and hence, not worth the effort.
But, oddly, they're insisting that Apple should write an entirely new operating system that undoes encryption, all by fiat, rather than via a court order.