That's old. I remember when I was a kid back in the 70s and early 80s reading a journal examining the quirks and foibles of modern society (OK, I admit it, I was reading Mad Magazine) and that has been going on for a long, long time. One piece in an old back issue made fun of the shrinking 5¢ (yes, 5¢) candy bar.
I've been eating a lot more fresh fruits, vegetables and unprocessed meats recently so it is harder to sneak price increases past me because everything is priced per pound.
Most people don't even know where to look for that price though. It is on a tag of the shelf the product is on. Takes all the guess work and figuring the lower priced product.