There are a number of reasons why battery swapping is not feasible in the real world, among them: - Batteries age differently from one another, so swapping would only be fair if you had a similarly aged battery that had a similar number of miles & charge cycles on it - Batteries need to be taken care of (like not using the last 10% at each limit of the battery). some people take really good care of their batteries, others don't. I would never want some random battery swapped into my car, as I've taken really good care of my car's battery - Batteries are structurally built into the vehicle, and making them easily removable would make a lot of the engineering more difficult - Batteries could become commoditized so that they fit in any car, but right now there are tons of different shaped & sized batteries, so it would be really hard to build the tooling to support all these different cars & battery types