In aggregate you might be right, but the issue is that people want to live in specific places and are willing to spend their disposable income to get what they want. As more and more people cross the threshold of absolute poverty more and more money is chasing the same physical assets. Housing is not a commodity asset.

In the long run, and in the aggregate (planet earth), but in a globalized world with capital from external economies (China) flowing into specific, highly desirable local economies, this old rule of thumb doesn't rule hold up anymore.