How is your answer in any way relevant to the topic?
Dodge my question a third time: How would Apple, a publicly traded company, appease it shareholders by installing a backdoor that allows access to a user's personal information yet only works when the device is physically in the possession of an Apple technician?
I could think of a few options. Having lived in corporate land a long time and adapted to changing regulations for almost 20 years, generally speaking the company is forced by law to react however possible. In my experience this involves creating new sides of the business dedicated to things such as finance, law, regulatory compliance, divisional security, auditing, I could go on and on and on.. the fact is, we do this today in various degrees.
Apple would be forced to create a division within the company to guarantee the safety of this data, think like a small three-letter-agency beginning with N and ending with A, to comply with the legal requests while protecting the data from criminals, foreign governments, rival corporations, and the computer hacking community at large.
It's the same way everything else works. Google allows this division access, likely with some strict and obnoxious bureaucratic process to record everything for future auditing and public releases, to be the ultimate authority on the customer data. Apple changes their corporate culture to follow suit using Google et al's already laid out plans and relationships, then proceed to change their use agreements to reflect this authority and they move on with their lives.
As for the technical, this isn't difficult at all. iOS already utilizes encryption past the seven key today, and from the perspective of encryption modification it's not the easiest thing in the world but is ultimately possible to do if forced to and would likely involve Apple getting compensated for this by the US government working directly in conjunction with aforementioned-not-named three letter agency to share a key pair that unlocks all iOS encryption. From there they can either do it through Apple and this division created for this purpose to protect the company (and, consequently, it's constituents, shareholders, and customers), or by accessing direct the same way they have plugged physical government infrastructure into the telco's today.
I guess I don't understand your question. What Apple is asking to do is possible, it's not an issue of technicality - it's an issue of law. I don't follow why you think otherwise.