I mean, it's great to suggest that cooking should be taught in schools, but if everyone in your house works I doubt anyone is going to have the motivation to cook on a regular basis, or retool their existing menu. It's not the physical act of cooking that saves you money, it's hitting a few targets:

Does it look good? Does it taste good? Is it nutritious? Is it cost effective?

If, as the article states, people have four core recipes and aren't making cost saving substitutions... then households have probably come to a subconscious decision that it simply isn't worth the time cost of figuring out substitutions. Inflation has just made everyone that much poorer.