I haven't met anyone who's replaced a battery yet. So far the batteries seem to outlast the car.

Most EVs are not old enough to need a replacement so no surprise you haven't seen it.

I've seen places offering to do it to a leaf. However the cost is more than the leaf is worth by the time it needs it. I know a few people with a leaf that has half the factory range left and they just deal with it because the cost isn't worth it.