Blackhawk is a peculiar case. Because I would argue that, even more than the Justice Society, the Blackhawks should be anchored to World War Two. It's what gave them purpose--the members of the team represent the forces allied against the Nazis and Japanese Imperialists and invaded by them. Yet, understandably because of their popularity, the team persisted after the war and continued into the late 1960s (going from one publisher to another in the process), so you either have to assume that the Blackhawks were long-lived or their origin kept updating to different wars. I think there was a theory that Blackhawk Island existed outside of normal time and space and that kept them young.

But you would think that efforts to reboot the team would go back to the original World War Two concept. Yet, after Howard Chaykin overhauled them, the next series after that in ACTION COMICS WEEKLY and then their own title was set in the post-war era. The main concern of these adventures seemed to be the Commies not the Nazis.

Plus you still have Lady Blackhawk existing in the present day.