We’d be much better off with airports that efficiently moved people from their initial location to their gate, and on arrival to their final destination, than with sprawling complexes that are cumbersome to traverse but accommodate more retail.
You can only sell off the airport’s future income stream once. Investing the money is new mega-terminals means not investing the money in things that would actually improve the airport most. As a result these choices mean the New York JFK travel experience will be worse than it otherwise could be.