That's $4.37 per box in November of 2025 dollars, according to the US BLS Inflation Calculator, for a box that was said to serve 4 -- or ~$1.09 modern dollars per serving.
A modern box of Kraft Mac and Cheese contains 7.25oz, and serves 3.5 [WTF?] people, and costs ~$1.24, or ~$0.35 modern dollars per serving.
Maybe if they weren't seeking the bottom dollar at every possible expense, they'd have held onto their sales.