Often in the comic books, they "update" things to keep the characters from getting too old. The Fantastic Four, for instance, instead of getting their powers by blasting off in a rocket to the moon in 1963 before the "evil" communists could, went to Mars in a spaceship much later.
What do you think of the possiblity of Disney's updating Mr. McDuck in such a manner? Instead of him striking it rich in the Klondike back in the 1920's (which would make him 105 or so), should they change in so he struke it rich in a fictional second gold rush in the Klondyke back in the 1950's- which would make him 70 or so?
They could even just say: "about 50 years ago" with no mention of date so it would be ALWAYS about 50 years ago from "Now".
"Rewriting history" is a "Ducktales" tradition.
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