In short, with sophisticated software, the thing can be managed to be profitable.
By the way, I understand that there is a start-up company (not publicly traded) that is developing software to manage the transfer of electricity between vehicles and the grid, as opposed to on-board software which manages only the on-board battery.
Why can’t I just buy a battery pack, or make my own from deep-cycle batteries, add a small fuel efficient generator, and the interface hardware, and make a couple grand a year?
Why pay for the rest of the car if this will be profitable to me?