A New Yorker piece by Dan Chiasson entitled “2001: A Space Odyssey”: What It Means, and How It Was Made" (4.23.18) basically explains how hipsters in 1968 saved the Kubrick masterpiece from box-office infamy. I've heard stories of how the peace and love movement took Kubrick's film as their own ("Dig that time-warp, man") but Chiasson really goes in-depth with the hysteria that was occurring in '68, just a year after the "summer of love" happened, and a year before Charles Manson would doom the movement.
"Hippies may have saved “2001.” “Stoned audiences” flocked to the movie. David Bowie took a few drops of cannabis tincture before watching, and countless others dropped acid. According to one report, a young man at a showing in Los Angeles plunged through the movie screen, shouting, “It’s God! It’s God!” John Lennon said he saw the film “every week.”
"In Harper’s, Pauline Kael wrote, “The ponderous blurry appeal of the picture may be that it takes its stoned audience out of this world to a consoling vision of a graceful world of space.” Onscreen it was 2001, but in the theatres, it was still 1968, after all. Kubrick’s gleeful machinery, waltzing in time to Strauss, had bounded past an abundance of human misery on the ground."
I wrote in 4.5.18, in a post called "2001: A Space Odyssey" is 50 years old today":
"A big studio film such a "2001 A Space Odyssey" could only be made in 1968, no other year, or decade, would have had a studio bank on this kind of big-budgeted, ambitious, and bold artistic statement. It redefined the way we saw cinema in a way that easily makes it the best, and most important American film of the last 50 years. It was filmed in 1967, during the "Summer of Love." Counterculture and LSD were at the forefront of mainstream art. Kubrick took this opportunity, the open-mindedness of a changing America, to make a movie that stood the chance of being accepted on its own unique terms. There is no other year where this could happen again."
“In other words, Kubrick’s film fit perfectly with the avant-garde movement of the period, the counter-cultural movement took it as its own, with even John Lennon uttering, “‘2001’? I see it every week.” And so, much to the surprise of the studio and the entire industry, “2001" became a movie event and the top grossing film at the box-office that year.”