I received a letter in the mail stating that there is a Sync 3 Nav update available. I have a 2017 ST3 with nav, so I thought I'd take a look... The mailer gives the wrong web address for information on obtaining the update, but I find it comical that Ford is charging money for this update, even if your car is still in warranty. $200 for the SD-card version, and $110 if you want to download it yourself.
Unfortunately, Ford does not own the rights to the maps. They are owned by another entity that licenses the content on a per device basis to Ford. Eventually Ford has to pay them for the cars sold that contain those maps/content/licenses/intellectual property.
An update, is not free to Ford; and Ford being in the business of making money, has no obligation to give it to you either. Your maps are not "broken," so I'm not sure how being under warranty makes any difference? I'm sure there is a good amount of markup from Ford for this, but that also covers the test and dev to make sure it works properly too. It's not like they are making millions here in GPS NAV updates... I bet tens of thousands per year at best, globally.
Go back 20yrs at least, and we used to have garmin or Magellan GPS units. Remember those? Well they sold map updates for those, even back then! Eventually you could buy a lifetime subscription for a reasonable fee, but that was only after cell phones became a threat to their business model.