On the cultural level, they have some similarity but not to the extent that they view each other as part of the same “nation” or “people”. One shouldn’t exaggerate the effect of speaking the same language: consider the fact that the US, Singapore, and Zimbabwe are all English-speaking officially (or de facto officially in the case of the US). Also Brazil does not even speak the same language as the rest.
Some differences do of course exist between the various US states but to a much, much lesser extent.
Germany and France (and the UK at the time) dominate. Poor nations like Poland and Greece with rich ones like Norway. Conservative countries like Hungary alongside progressive social democracies like France and Sweden.
I doubt there will ever be even an EU-like structure encompassing Latin America, but even if there is, that would be a far cry from becoming a united sovereign state.
I misremembered it as San Martin's opinion while old and dying in France, but it appears to be the description given by Karl Marx to Engels (apparently on a letter sent on 1858-02-14, though I can't find that letter right now). This article [0] on the Metapedia explains a bit of the history on why Marz was talking about Bolivar, but also says that modern marxists don't share this view.
[0] https://es.metapedia.org/wiki/Karl_Marx_contra_Sim%C3%B3n_Bo...
It’s hard to bring people together when they speak different languages and have to take a plane or cross difficult terrain to meet each other.
South American is already mature. The countries there have different political situations and relationships. Trying to bring them into one federal republic is a non-starter -- it ain't gonna happen.
A better model would be the EU where you have mature countries removing trade barriers between them, allowing free immigration, and a single currency. This was anchored by a few large countries that had relatively low corruption, peaceful relations and strong economies.
South America... doesn't quite have a strong set of low corruption and strong economies. There are regular coups and a number of ongoing civil wars that would make trying even for a loose coalition of countries in South America difficult.
Again - internal self sufficiency is not the basis of development.
S. America has relatively free trade for things they need, and there are no hugely relevant issues there.
The wheat innovation is going to be nice for Brazil, but more as a function of expansion of industry, not really on the basis of 'self sufficiency'.
Brazil's path to wealth lies through the reform of civic and social institutions, not through some kind of magic grain.
The same could be said of most places.
