Making batteries exchangeable adds a lot of costs and overhead. The battery changing infrastructure is even a greater nightmare. Nio tried it and failed. With batteries getting better and better, this concept also is getting less and less feasible. It is really easier and cheaper to expand infrastructure of long range EV renting. That said, in Europe taking the train and renting an EV at the destination (range is not much of an issue then either) is probably the more relaxed option anyway, if a car is needed at all.

Why not a city car EV and just rent another car when you need to make long journeys?

Or for me in the UK, why would I want a car, you can't even drink in it. Trains have staff to sell me a drink.

Go ahead with your idea. You might discover how the American consumer really feels about EVs.

Home charging is easily better for city car. Only two use cases for changeable batteries are commercial two wheelers and trailer trucks. And for trucks you'll need to change out the driver too. There are ones being trialed which use a forklift to change it out.

Most cheap EVs have a battery you need to rent, and they are "standard" to the company (proprietary)