I dont know much about vending, but didnt Topps make Vending Machine Boxes of sports cards? What were those machines? Couldnt they be set to dispence a pack? Like i said, i dont know but food for thought.
You're right that sports cards were sold in vending machines in the sixties, but they were sold by the individual card, not the pack.
I've never seen one of these machines, and I'm pretty sure the practice was discontinued by the early '70's.
Of course, Topps continued to make these "vending boxes" throughout the '70s and '80s. By then, I believe they were mostly sold to dealers like Larry Fritsch and Renata Galasso who put together sets to sell on the secondary market. I remember visiting the Galasso factory in Brooklyn in 1977 and buying two vending boxes for $5 apiece, because I was bored with just ordering the complete set.