'They aren't making any more of it'

Conventional wisdom has it: "Invest in real estate--they aren't making any more of it". While it is true that when rising demand meets fixed supply, the price must rise, that's not the whole story. But the supply of urban land is not fixed, but rather expands in response to transportation improvements. Development of skyscrapers and multi-story retail ceased with the advent of the automobile age--cheaper, equally accessible land was available on the urban fringe.