That's not true. Standard batteries can be switched in or out, and there are different types, brands, etc. I know EV batteries are bigger etc, but I think it's comparable. They are just batteries.

In EVs though, replacing the battery is so expensive - thousands of pounds/dollars - it makes no sense to do it. So once the battery starts degrading after only a few years, the upgrade is incredibly expensive - essentially the cost of a car.

If by doing so you could at least extend the range and see a benefit, perhaps it would make sense. And why couldn't you do it. Because its a design anti-pattern. If you stick to a certain space in the car for the same model, you could easily make this a feature. But you wouldn't if you just want to sell cars.

As it is, I think these cars will have a shorter life span than non-EV cars - they will be scrapped earlier as they are not economically viable. I don't see how they not far less environmentally unfriendly than non-EVs.