Right.
I know in the 1970s there were "collectible" glasses in jelly jars that could be later reused as drinking cups. And a detergent company attached a series of Pogo plastic cups to sell their wares.
And some fast food burger joints would offer collectible glassware for sports teams. And 7-eleven went overboard with dozens and dozens of plastic slurpee cups in a year.
I seem to recall Happy Days glasses at some fast food joint but the Star Wars glasses (at Burger King?) really brought that trend into focus (at least for movie critics).
I think it was Roger Ebert who identified a class of movies that could have their plots summed up on 4 (or 6) glasses.
Now that I think of it, King Kong (1976?) also had such glasses.
It certainly became a standard for the Lucas films to come.
And while other movies might have a set of trading cards, I think the original film had 3 (or 4?) series of images from the film. At a time when there was no home video (and not even a telecast of the movie for years to come) it was one of several "home experience" ways of reliving a movie (there were also some sort of photonovels in the 1970s).
I recall the “King Kong” slurpee/icee cups (might still have one around here somewhere). Seemed to be the first tie-in of that nature that I recall, although in reality it doesn’t seem too far removed from things like “Six Million Dollar Man” gum cards, or earlier, 1960s-vintage Dell ‘movie comics’ or tv-show board games or big little books. There were also some “Planet of the Apes” gum-cards, which preceded the “Star Wars” sets by a fair number of years, although it was definately the latter which seemed to start a trend in movie-themed card sets (with “Close Encounters” cards hot on its heels). I seem to recall the “Happy Days” glasses coming after the “Star Wars” merchandising phenomenon, albeit very shortly afterward. The “Happy Days” comic book didn’t even start until 1979, which even then struck me as being too late in the game, as the series was well on the wane. Whatever the case, “Star Wars” was definately a demarcation point in the nature of merchandising and tie-ins.