From my experience it seems like certain its a bit of give and take in terms of costs for food inputs. Argentina is typically cheaper for meats. Fruits and veggies I find are cheaper or similarly priced as in other latin countries. Foreign brands are typically higher, again, same as in other countries but here moreso.
Some things are based on sizes. Shopping is typically limited to the day of or a couple days, not filling up carts and trucks for a week or month of food. They buy 500g/1kg packs of rice instead of 11kg sacks like in other countries. It is still around $1/kg or less.
The veggies would be about 25% cheaper at least in the verduleria than the supermercado. Cheese at the supermarket in ready to go packs is more expensive than the kioscos here, but you can buy blocks of it for super cheap if you buy it in larger quantities.
Also, when one considers the local diet, I find they are typically eating a single larger meal per day and either a lighter one and almost no breakfast, or 2 very light meals breakfast and mirienda (I think its called). The diet will also consist of a lot of eggs, pastas, a lasagna, pizzas and sandwiches, all typically homemade. So while certain meals may cost more, other staple meals are very affordable.
In other latin/carribean countries, things are similar. Looking in supermarkets it can be expensive, but the daily meal in some places is rice with beans and eggs or chicken, and platano based dishes.
The thing that strikes me the most is really the supermarket business model. I really don't understand it here. Typically, its a low margin high volume business with a few profit centers (produce, cheese/deli/meat/fish counter(s), fresh bakery). Here, they just jack up the price and reduce the volume sold, while still paying their rent. For the over 3 years I have been here, they just continually kept reducing the number of shelves, displays etc and changing the layout slightly and kept offerring fewer and fewer goods. It, Libertad in the mall here, finally closed but another supermarket is coming in. Carrefour also expanded to 24 hours, or at least had a sign out a week ago that they had so that is nice.
I don't know if it makes too much sense to compare Carrefour here (neighbourhood corner shops, basically), with Carrefour in France (upmarket hipermarchés). If we want to directly compare supermarket prices, maybe Aldi or Lidl in Europe would be more appropriate.
I think Carrefour here has two brands of stores, Carrefour the supermarket, and Carrefour Express, more tightly packed stores throughout CABA that are much smaller. In my city there is only Carrefour the supermarket.