This Movie Was a Hit in Theaters for Years
It was somewhat ironic. Robert Redford had all these roles where he was nicely clean shaven and in suits and smiling all the time ("The Candidate," "The Hot Rock") that didn't hit very big, and then he makes this rather downbeat (but ultimately uplifting) epic where he's all hairy and bearded and killing Indians...and it was a big hit.
But in a weird way.
In the early seventies, video/DVD didn't exist for general consumption and even cable TV was in its infancy.
So "Jeremiah Johnson" just sort of kept playing and playing. Then it would go away. Then it would be re-released: "Jeremiah Johnson is back." Then it would go away again.
"JJ" was a Christmas 1972 release; a year later in '73, Redford hit bigger still with "The Way We Were" and "The Sting" -- so they brought "Jeremiah Johnson" out yet again. And then it went away again.
And came back again: in late '74, I finally saw it. In a theater. As the main feature!
"JJ" was such a hit, it is believed, because it forcefully connected with a 70's youth culture (and perhaps their wistful middle-aged parents) who dreamed of getting back to nature and living alone in the rugged outdoors. It was also jokingly called "the Birkenstocks and granola Western."