You only talk about why it can't be done :D. Modern apps could show the current stock of stations. Batteries could be modularized. So X car might need 4 piece

You only talk about why it can't be done :D. Modern apps could show the current stock of stations. Batteries could be modularized. So X car might need 4 pieces. Y car needs only 3 etc. Bring in standards about car battery spacing etc. If the station runs out of batteries, just use the backup option, meaning, charge the battery in the car. Anything else needs addressing? :D