If I ruled the world...
... all "shrinkflation" products would be required to have a notice on the package that says:
SHRINKFLATION ALERT!
Former weight: X ounces
Current weight Y ounces
You now get Z% less
And that notice would be required to take up at least half of the available label space on the package.
Look at this bullshit:
https://i.imgur.com/EWDohcJ.png
It's no wonder that a box of that stuff used to fill me up in the 1980s and 1990s but now it feels like a light snack. Oh, they ditched the peas too, for good measure. I'm sure that saved them a whopping $0.000001 per box.
5.5 ounces isn't even as much as you get in a box of Kraft Macaroni & Cheese (7.25 ounces), which, by the way, has only ever had very minor shrinkflation (its original weight when it came out in the late 1930s was 7.5 ounces - https://i.imgur.com/n4AxkLL.png).
Since Kraft Macaroni & Cheese is the same idea as Tuna Helper (they both consist of a small envelope of powder and a small amount of dried pasta), it's a good point of comparison. These are the current prices at my local grocery store:
Kraft Macaroni & Cheese - $1.29 for 7.25 ounces
Tuna Helper Creamy Pasta - $2 for 5.5 ounces
Oh, and that 6.5-ounce can of tuna mentioned on the front of the old box of Tuna Helper; that's a victim of shrinkflation too. The "standard" size now is 5 ounces. Hell, even that 6.5-ounce size was the result of shrinkflation, because I remember when the standard size went from 7 ounces to 6.5 ounces when I was a kid. There are some recipes in an old recipe book of mine that call for 7-ounce cans of tuna.