Why does anybody think that if children are given bread for lunch, it'll be all they eat? It is one meal of their day. It is up to their parents to see that they have a balanced diet overall. If you are buying in quantity (and we were talking about schools providing lunches) then you could do a reasonable amount for £3.50. Obviously things have changed recently due to rising inflation.
The majority need a good balance of carbs, proteins and vegetables. The Healthy Food Pyramid which is what the Government advices puts Carbs at the base of the pyramid. Now, personally, I am not convinced but that is the current recommendation. The beauty of bread is that you can add vitamins, etc and you can also make it with other things in it to make it more nutritious like grains, sunflower seeds, olives, tomatoes, cranberries, etc, etc. The alternative carbs like pasta are no better for nutritional purposes unless you add something to them but they are filling and they slow down the blood sugar spike.
As a diabetic, my bread intake is minimal but then so is pasta and potatoes but I don't think that the diet I eat is necessary for non-diabetics.