Well, Buenos Aires was considered on par with American and European cities in the early 20th century, but chronic political instability hindered Argentina throughout its history. That, and much of its economy at the time was dependent on ranching, which hurt it when food prices dropped.
Argentina is one of those nations that I think could have been a respectable power if it had better governance and if other countries stopped exploiting its economy for a while (e.g. the financial crisis of the late 90s). The 20th century hurt its standing a lot, especially after a coup in the 1930s if you believe the Wikipedia article. The satirical comic Mafalda written in the 1960s and early 1970s often makes jokes about Argentina being underdeveloped and everyone wanting to flee the country, hinting at its poor economic shape at the time.
(Read Mafalda if you know at least intermediate Spanish by the way. )
I like The Penguin History of Latin America for a general resource.
Through Five Republics On Horseback by G. Whitfield Ray has a portrayal of turn of the century Buenos Aires, though the author's prejudices will make you roll your eyes. Take that book with a shaker of salt.
The Gold Diggings of Cape Horn by John R. Spears can be found for free digitally and gives some perspective on the Patagonian gold rush of the 1870s.
EDIT: I study Spanish South America a lot more than I do Brazil, so I probably won't be much help there. The Penguin History of Latin America has a good amount of information on that country though.
could argentina stand better chance(s)?