My biggest problem with Indiana Jones 5 isn’t that Indy is too old (I mean he drank from the True Grail so normal rules don’t apply) so much as the issue that the whole franchise doesn’t feel like something that belongs in the 1970s.
The Indiana Jones movies were at their best when they were an homage to the action-adventure serials of the 1930s and 1940s, with bad guys that could be killed without hesitation or remorse (Nazis) and entire long-lost civilizations waiting to be rediscovered.
It just doesn’t feel like the kind of movie you’d ever want to set in the disco era.
