Actually economists do believe the US gains leverage to print money from the dollar's status as the world reserve currency. The key phrase is "exorbitant privilege", from a phrase coined by Valery Giscard D'Estaing in the 1960s, and there is a book of the same name by Barry Eichengreen. It's true that this hasn't been used because independent central banks have been restrained since the 1980s. But in general it's still true that US monetary policy has a huge effect on the rest of the world. For example, the Latin American debt crisis of 1980s was linked to the tight monetary policy of Paul Volcker.
