I'll expand my comments. In the larger historical sense, covering the whole history of the American Republic, the execrable Tom Brokaw's term "Greatest Generation" is simply wrong. In the narrower historical sense you suggest, it is both dubious (the "Great War" generation was still living) and fatuous. If the other living "generations" did not have the opportunity to demonstrate their greatness, then their greatness cannot be evaluated and there is no point of comparison.
Finally, I reiterate my final comment from the previous post:
In fact, this whole business of trying to force-fit millions of people into "generations" that all supposedly think and act alike is foolishness. It is leftist group-think at its absolute worst.
GMTA!
My sentiments exactly.