The argument was convincingly made in 2014 that the true break for Argentina came in the 1970s, when the military government embarked on a period of misgovernment that resulted in lasting damage.
https://moneymaven.io/economonitor/...-a-century-of-decline-4hGmoqTg9EyqcwCcevCtjQ/
I quote the author, Eugenio Diaz-Bonilla:
This structural break in the evolution of the GDP per capita (GDPpc) in Argentina can indeed be attributed to internal conditions in that country. But other than that, there is not much difference in the evolution of Argentina, when compared to, for instance, Australia, or Uruguay, two countries mentioned by The Economist as either not having suffered the “hundred year decline” and/or to have followed better economic and institutional policies than Argentina. It is true that other countries such as Korea or Spain, which had far lower GDPpc than Argentina during great part of the 20th Century overtook Argentina by a large margin since the 1970s. But it is also true that if Argentina had avoided the sharp drop in the 1970s and maintained the share of the US GDPpc that prevailed before that structural break, the country would have had now an income per capita above all countries in LAC and many European countries such as Portugal, the Czech Republic, Hungary, and Poland. And if it had maintained the lineal trend growth from the 1960s to the mid 1970s it would be now at about the level of New Zealand or Spain, according to the data of the Maddison Project. In other words, if Argentina had avoided the real tragedy that started in the mid 1970s, the country would be now a developed country.
Assuming that you avoided the 1970s meltdown of Argentina, and the country did evolve along the lines suggested by Diaz-Bonilla, you would have in South America a country as wealthy as Spain and with a population perhaps four-fifths the size of Spain's. (Argentina, I suspect, would if it remained a stable and prosperous democracy have seen rather less emigration; it might even have seen more immigration, from South American neighbours and from elsewhere.)
Would this be enough to meet the initial proposal? I have my doubts: I think Canada under estimates itself, but I also think Canada is far from being a global power along the lines imagined.