A theory of economic boom and crash is one of George's two great purposes in Progress and Poverty. George says that the speculative rise of land prices cuts into the earnings of labor and capital.
Land is needed for all production.
When sufficient numbers of workers and capitalists cannot afford to produce at the higher rents brought about by growth and speculation, production begins to stop. If builders must pay too much for building sites, it takes from their profit by raising their costs. Their profit on investing in the building itself is what stimulates investing, which in turn is what makes jobs and incomes. You be the judge. Trump held the site, looking just like this, for about fifteen years.