you believe Apple ?
At the moment, yes, for a very simple, ultra-American reason: they make money that way. Apple figured out early that security was a sales argument and has worked to keep it that way.
I can't predict what will happen when it becomes more financially beneficial to ship flawed hardware, but I do know that Apple would lose a fairly vast chunk of its client base if anyone discovered suggestions of a backdoor so I suspect there will be a major barrier for Apple to change its ways.
Follow the money. It's the American way.