The only thing keeping the US economy from falling off a cliff is AI spending : Without it, the nation’s growth numbers would be in the toilet, dragged down by an Iran war that’s goosing gasoline prices and sending US consumers straight to the poor house. That, at least, is the doom-and-gloom making the rounds in the mainstream media and on some parts of Wall Street lately — with Cassandras adding for good measure that the artificial-intelligence bubble is poised to pop any day now, leaving