The pro-land value tax response is that, if someone really believed people highly valued washing their cars in the city, one could open up a car wash on expensive land. If people really don't want to drive 30 minutes but also really want to wash their car, they can pay more to use this expensive in-town car wash. It is of course possible that the economics wouldn't make sense to support such a use of urban land in the densest/highest value areas.