Don't picture them as OTA firmware updates. Picture them as OTA navigation data updates (i.e. maps, charts, waypoints, airport info, etc...) - that's much easier to pull off.
The process right now is pulling out an SD card from your Garmin/Avidyne/BendixKing whatever every 28-days or so (that's how often the FAA updates the navigation database backing these avionics), popping it into your PC, using software/webistes that could be... much better designed (to put it lightly) and then going back again. It's not exactly the hardest thing in the world, but it's not exactly a walk in the park either (especially for less-technically inclined pilots, who just let it lapse, and click out of the big expiration warnings every time they start up their planes).
The process right now is pulling out an SD card from your Garmin/Avidyne/BendixKing whatever every 28-days or so (that's how often the FAA updates the navigation database backing these avionics), popping it into your PC, using software/webistes that could be... much better designed (to put it lightly) and then going back again. It's not exactly the hardest thing in the world, but it's not exactly a walk in the park either (especially for less-technically inclined pilots, who just let it lapse, and click out of the big expiration warnings every time they start up their planes).