See also the story of TropeTrainer: essential software for learning Torah chants, which suddenly disappeared when its only author died and his widower wasn't prepared to continue selling it.
There are (at least) two separate cases of artificial vision systems (one a bionic eye, the other a brain implant) being completely abandoned with the devices still implanted in patients' heads who were never informed of that risk. One is the Argus 1 and 2 mentioned here, the other is the Dobelle AVS which went the same way as TropeTrainer after Dr. Dobelle died. And unlike most software, this has put patients in an emergency medical situation before, with no one to turn to for help. (I won't go into details, too graphic.)