Something similar happened with the Big Mac in McDonald's. At some point the price of the Big Mac was like 30% lower than the other similar hamburgers. Inside the restaurant, you had big advertisements of the other combos, hamburgers and premium hamburgers, but the Big Mac appeared only in the small list of prices in the corner. I found this link with more details https://www.pri.org/stories/2012-02-07/argentina-likely-mani...
That's actually extremely cheap by international standards, if this source[0] is to be trusted. Of course it seems expensive for most argentinians because wages are also terribly low.
[0] https://www.numbeo.com/cost-of-living/country_price_rankings...
All in all, I doubt that number is entirely accurate. Argentina is a _very_ large country, and even the minimum price varies greatly depending on the region.
I have family in Patagonia, for instance, and they tell me it's impossible to get the cheap milk brand over there.
I'm sorry, could you be more specific about what it is what you saw?
There are no "government mandated prices" in this country, at least not like you make it sound(Apologies upfront if I miss understood you).
There is a government program where all big market have to carry products where their price is fixed by the government. The idea is that you can always have the chance to go for a cheap product if you are poor, but it's not for instance that all milk brands have to have the same price.
And milk can get pretty expensive pretty fast in this country: It always come in 1 litre recipients, and the cheapest one (The one that is within the mentioned program) is right now at ~70 pesos (Some 73 dollar cents at the official dollar price, 40 cents at the current rate for the dollar in the back market... but foreigners can hardly get this price for their dollars).
I don't know what the prices are in other countries, but I think tourists will find prices rather high compared to their countries once tourism starts again.