But I think that once all the retirees who were insufficiently dextrous or mindful enough to handle opening the back of the camera and remembering to rewind the film bought theirs, that market was pretty well saturated.

Screwing up film loading/rewinding remains an equal opportunity affair. APS sold well in Japan largely for its convenience and its compact cameras. Processing was never as cheap as 35mm. There was also the surprise on pick-up of different prices for the variable-size prints that pissed off customers.