You might have to forgive them, if they’re talking about their folks with the ear marked “20 years” they’re likely old like me and think that means 1970. Us old folks tend to think “20 years ago” means 20 years before 1990’s. It’s a common mental flub.
That would make the inflation value closer to $0.38 in today’s money. It’s not a lot, but when you’re getting almost 8x the amount for each can, it adds up.