The loyalty thing has a lot to do with the growing up..
not to be stereotyping or whatever, but Argentina always had a pretty high level of education and generally the players are taught about more than just football. Argentinian players are always outspoken and have more to talk than just about football, Valdano, Zanetti, Redondo etc. are good examples.
Even Maradona, who had maybe 8 years of school, has something to say.
Personality is much more built in Argentina than in Brazil.
On the other hand, the Socrates generation of Brazil was from the personality perspective the greatest generation ever.
and about the world cup...argentina was robbed of its best generations. Di Stefano was Argentinian, but at his time in Argentina, there were no world cups(late 40ies, early 50ies he moved to Spain). That 40ies team of Argentina was one of the better generation, same as 1934 and 38.
You can also see that from the Copa Americas Argentina won in that time.