This is a very tidy theoretical argument, but in practice you don't build a warehouse in a rural area along a shipping route then just abandon it when the community unionizes. Companies stick around for as long as they can possibly make a return on that investment, even if it means paying the people at the top less or decreasing margin to comply with union demands. And yeah, unions can go too far, but Amazon warehouses seem like a great place for them. Also, as long as the state is right to work so union participation is voluntary, what's the problem with it?