One thing that accounted for those top box office draws is that epics (and classics) would be trotted out for theatrical re-release every so many years.
Disney seems to have stopped rereleasing their cartoons theatrically to each generation.
Home video has replaced it (and they put product “in the vault” to build up cyclical demand).
The big thing Star Wars did was usher in high dollar franchises. James Bond came around again and again but with new actors in the lead and without a continuity.
There were 2 Godfathers and 5 Planet of the Apes films and you probably couldn’t get very far coming into the middle of the storyline.
Before that the “Franchises” were Boston Blackie, the Bowery Boys, Charlie Chan, Ma and Pa Kettle, etc. B-movie companions to the A-movie on a double bill.
“There were 2 Godfathers...”
What about Godfather 3?
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Wait. You know what? Never mind.
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There were 2 Godfathers