@tirynn It happens because the manufacturers are dealing with rising costs themselves. The price of everything going into the food goes up, so manufacturers do this not to necessarily make more money, but stop making less. Or, the real killer cost can be transportation and storage, and as fuel and real estate prices go up, so will the costs of goods.
So, cost/weight will increase in two ways. One year, they will just raise the sticker price on the shelf. Sometimes the store does this themselves, sometimes it's because the manufacturer raised the price that the store bought the product for.
The other way is to "down-count" the product, getting less for the same cost. It's entirely reliant on human psychology of people knowing a container of product X should cost $Y. They'll notice if it starts costing $Y.50, but just take longer to catch on.
The whole process still costs the manufacturer money. Developing new packaging - even if it's the same size, you need graphic artists to develop a new design with the new quantities. Then, you need to create a new UPC code, and that whole process is stupid expensive.
But, here's a fun fact. Anything that says "double" or "25% more" or whatever is an actual legal obligation by the manufacturer. Meaning they have to actual produce a version of the "regular" size. Doesn't mean it's for sale at the same store, but they have to sell it. If you can find these regular sizes, they will sometimes have more product in them then what is declared on the package.
Why? Because as manufacturers down-count/shrink how much goes into a package, they sometimes eventually hit limitations on their equipment and it could be too small to package efficiently. So, there's no law against over-filling the package. So, and a very small segmentation of their offerings, it's possible that even though that roll of toilet paper might say it has only 120 sheets on it, but it may have 150. Doesn't matter, because more profit is made selling the 240 "doubles".