Either a developer has land or must reuse existing land and buildings. It is that basic. Think of a manufacturer of a widget who has increasing demand but can't find the materials to produce it. At least he can go global to find the materials which may result in higher costs, but he will find his raw materials. When the basic raw material is land, it is not a widget and cannot go global.
Land is always local.
When greed assumes control and local industrial and office rents are no longer competitive with other cities, and jobs depart. I do not mean the guy standing on the corner, holding a sign asking for food. I speak of the true middle-class which is necessary to keep an economy humming. When they begin leaving and they stop arriving, then the boom is over. When lenders become much more selective in allowing more new construction.