If you look at Confederations Cup last tournament, the Brazil biggest scorer was Fred (Fluminense-BRA), the only scorer that had obtained 5 goals without doing half of them against Tahiti. The golden ball was with Neymar (Barcelona-ESP, but called still as Santos-BRA), and the bronze ball was with Paulinho (Corinthians-BRA, now Tottenham-ENG). Jô, Réver and Bernard (all from Atlético Mineiro-BRA) were also highlights of tournament.
Argentine has been passing for a hard moment, but, in fact, both Brazil and Argentine often don't call players from both domestic and foreign leagues, even in FIFA friendly dates or FIFA official competitions (like the qualifications for World Cup). The reason is very understandable: test a bigger number of players in different contexts (friendlies, competitions, etc.). Choosing only the best players of your domestic league don't make it a B-team (the super-winner Spain, for example, calls almost only calls player of its domestic league) and the fame of a player is no way directly related to his skills.
And I don't know why the hell people still see the squad of these matches as B-teams. The first Superclásico, for example, was among the best performances of Brazil led by Mano Menezes.
I understand perfectly the problem with the fixtures. A top team plays, every year, 38 matches of national championship and 20+ matches of state championship. Additionally, he'll play Libertadores da América or the Brazil Cup and, in the end of the season, the South American Cup. Eventually, he'll play the Recopa, the Suruga Cup and the World Clubs Championship. I.e. a Brazilian team can play 100+ official matches in a year (discounting pre-season and inter-season friendly matches and tournaments)!