Well we know that Apple already did assist with the case in some ways — they provided the iCloud…

For Apple to assist with hacking this iPhone, (a) they would have had to lie about their inability to comply with the order in court, (b)…

Well we know that Apple already did assist with the case in some ways — they provided the iCloud backups to the FBI. And we know that in past cases they’ve been able to help extract non-encrypted data stored locally on phones as well. The point of this case, though, was that neither Apple or anyone else could access any of the local data without knowing the passphrase that unlocks the encryption key.

For Apple to assist with hacking this iPhone, (a) they would have had to lie about their inability to comply with the order in court, (b) the FBI would have had to lie in their court filing that an unnamed “third party” was providing assistance, and (c) the FBI would have had to persuade some of Apple’s security engineers to actually do the work, which is doubtful given that many were ready to resign if Apple lost the case.

Could all of these parties have conspired together to make this happen? Sure, but I find it much less plausible than the current narrative.