It's not a guessing game at all. The prices they paid back then were equivalent to what a $9 ticket costs now. Gas at 10 cents a gallon or whatever it was back then is like the $2.50 or so we are paying now. The value of whatever a movie costs to see back then, say 25 cents, is equal to the nine dollars it costs in todays terms. If you don't adjust for inflation no old movie can ever compete, and all of the Stars Wars will be out of the top 10 in 65 years, because movies will cost $20 to go see, or whatever inflation brings it up to by then. It has nothing to do with if people would go see the movie if it were released today.