The reason is simple. I have read the book he wrote that got him a Nobel prize in economics.
The book is Geography and Trade. Published by MIT press in 1992. It is about 150 pages short.
The book is largely an indictment of economic theory. In the 200 years that men have been developing economic theory no one has ever previously noticed that industries tend to grow up in limited geographic locations. Weaving and fabric processing were pure New England. Clothing manufacturer was in the Carolinas as was rug production. Computers and the Internet were Silicon Valley and San Francisco. Automobiles and before them carriages were Detroit.
Those are the observations that Krugman’s book is based on. He was simply calling economists attention to the facts than any businessman has known for a century. Not a man of insight. Just seeing the obvious one hundred years after the ordinary businessman.
He ain’t right about anything else, he ain’t knowledgeable about anything, he is merely a political ideologue who writes a uniquely dishonest column for the New York Times.
I saw the same dishonesty because he advised the Japanese government from the early 1990’s to the late 1990s in how to deal with the real estate bubble and ensuing economic turmoil. He was in favor of using Keynesian debt financing. The Japanese followed his advice. It never worked. After hurting millions of people, he always said more debt financing was necessary. He never learned from his own experience because he is ‘uniquely dishonest’.