I opened two cans of beans not long ago. Same price, same weight, same size.
Can #1 was packed to the top with beans.
Can #2 was 3/4 full of beans and water the rest of the way.
I’ve also noticed that in canned tuna and many other products.
Several years ago I bought a certain brand of dish washing soap.
Then one day the IMPROVED(!) the bottle by making it easier to grasp by making the diameter of the container smaller. So, for the same price as the large bottle, I now got 1/4 less for the same price!
I used to eat tuna fish and crackers for breakfast several times a week. Tuna in 2007 was 50 cents. Tuna today is $0.95.