Once they get Autopilot and FSD fully functional I would hope Telsa would add the features On-Demand. Since the hardware is on-board, especially the new models with version 3 computers, it could be a good revenue stream. Basically what I am proposing that you could purchase these features by the mile or by the hour. This would also be a good stepping stone to robo-taxi subscription model. If it raining you might be willing to shell out 10 bucks for a single use advanced summon.