I'm not sure it's fair to compare a very specific food item which enjoys massive economies of scale when prepared industrially the McDonald's hamburger is. Like, of course a homemade hamburger of that type is going to cost more and take a bunch of time— when I make hamburgers at home, I make them from scratch including baking my own buns, but the result is not a $1 McDonalds style burger, it's something that would be $20+ at a gastropub.

More realistic would be to compare the food value derived from a $1 McDonalds hamburger with what $1 can buy at a discount/bulk grocery store in dried beans, sweet potatoes, onions, and other high bang-for-buck items.