That is amazing it was in theaters that long though I guess that was before home video of any kind. Only chase to see it was in theaters. I do remember the nets broadcasting some hit films, specifically ABC, when I was growing up in the late 70s/early 80s. Did they do that in the late 60s at all? Was that an avenue for a film after its run was television broadcast?
I do remember the ending specifically being mentioned as this "trippy" ending that cast it as fitting into the late 60s zeitgeist. But interesting you mention it was only after the film was out and through word of mouth and not marketing.
I could probably use some drugs until this election is over.

Coffee will have to do I guess.