I don't often repeat myself, but for the sake of answering this question I'll quote my question above.
How do we know which version of NAV maps we have on our Entune system?
These updates should be provided for free, once you've bought the $40,000 plus vehicle. Toyota could offer an email notification with an update you could download through a micro SD card through a card reader. Camera makers do this for their better cameras and it works flawlessly. Some use a direct connect of the camera to the computer, which wouldn't be practical for a car. Wireless connection wouldn't work because in the case of cameras, if the download is interrupted for any reason it turns the camera's OS into a useless brick. But apparently Toyota already uses a microSD card for updates.