I suppose if they churn (pardon the pun) enough units of ice cream, they may save a bit of money by cutting the size. But the cost of ingredients is generally one of the smallest input costs. Maybe cutting an ounce or two saves them a nickle a unit, give or take. The price of the containers, shipping cartons, plastic pallets, maintenance of filling lines and freezers and freezer trucks, overhead and labor, advertising, weekly discounts etc etc are probably all rising relatively more than the cost of the ingredients in the ice cream.
Inflation has been going on for years....you get eight oz of cookies for the price you you used to get sixteen oz....everything no the shelf is like that...
You’d think ice cream ingredients would be next to nothing when the dairy farmers where crying over “supposedly” dumping milk on the ground.