“Rav Moshe isn’t always the final word in America either. Roshei Yeshiva and Poskim, such as Rav Hutner, Rav Eli Meyer Bloch of Telz, the Debreciner Rav, the Chelkas Yaakov and others, sided with the Satmar Rebbe over Rav Moshe regarding the obligatory size of a mechitzah in a shul”
Yet we stuck with Reb Moshe’s psak. That whole example just provides more evidence that he was the final word in America, even when other respected rabbis disagreed.