IMO, a lot of the things that APS did or at least tried to do might have been able to be done by 35mm stock with either a magnetic stripe on it (like APS has) or even optical imprinting on the rebate. Use the 35mm format could have allowed Kodak to use only one film to fill both types of cassettes. I also believe that if Kodak was really and truly thinking ahead to today they might have even made it so that the cameras could have been adapted to use a standard 35mm cassettes after APS cassettes went out of production.

As others have said, that magnetic strip and odd film size ensures that APS cameras will go the way of the Kodak disc.