So we measure greatness by time now? There are many countries far older than the U.S that I wouldn’t consider great by any standard.
Nazi Germany was never “great”. They were vile and amoral as the day is long. Murdering your way to the top simply doesn’t count as “greatness” by any rational measure. Now the german people themselves have a great historical legacy, but that aberation called Nazi Germany was just a brutish coup by criminals during a perfect storm, defiling and squandering what took centuries to build.