Of course that could be the reason, but I just saw the article where Ford touted the ability for the dealer to add Navigation to a MFT system after the fact.
I think they simply don't have the logistics in place for the customer to pay for the feature and for the dealer to install the software yet. All they would have to do is have the dealer sell the SD card upgrade for $795 or $895 or whatever and the dealer installs it. Since the SD card has to be authorized with the installed software that should prevent piracy.