I don't think there was any real quality differential between Falcao and Redondo. Certainly nothing significant enough to have them in a different tier.
I think Europe probably does have greater depth in central midfield but I don't think the examples highlighted are great ones - IMO the likes of Gerson and Varela are comparable in terms of quality to Breitner and Masopust.
It does however look to me like Europe has a much deeper pool of players in that secondary tier - just from the UK/Ireland you have the likes of Keane, Souness and Robson who were all at least as dominant as some of those South American midfielders listed. I think we could comfortably name 50 European midfielders as good as Dunga for instance.
It's noticeable that Xavi isn't mentioned either and when the dust settles on his career I think he'll be held in higher esteem that any South American midfielder, including Falcao/Didi/Redondo. Time will tell there however.
I think the problem with depth in relation to Eurocentric considerations is going by those whose legend is known in Europe, when, there are many, many others who are legendary on the S.A. continent that not much is known about on these shores.
Some midfielders for consideration who are easily peered with Europe:
Sastre, Toninho Cerezo, Zizinho, Andreolo, Alberto Terry, Cueto, Sotil, Victor Benitez, Jose Velasquez, Modesto Bria, Ruben Marcos, Vidal (the active current one), Mascherano, Simeone, Riquelme, Dirceu, Paulo Cesar Caju, Denilson Custodio, Lazzatti, Dino Sani, Trobbiani, Fleitas Solich, 'El Charro' Moreno (could be played at AM), Norberto Alonso, Merlo, Martim, Alemao, Pampolini, Quintanilha, Veron, Jair, Lima, Carpegiani, Jorge Jose Benitez, Francescoli.
The list of players can go on, but the point is, there's more than enough talent pooled to make an almost endless amount of quality sides. It's at the back and especially at keeper where S.A. will fade quickly, but equally, or conversely, the same goes for Europe in attack once all the elite talents are thinned out the standard will drop similarly.
The caveat for South America is that many of these players didn't shine at NT level because their paths were blocked by even better players who have been mentioned by
@Aldo there's also politics, too. Europe, with its multiple nations, would obviously give an equal talent pool more opportunities to shine, but, if those same names were concentrated in the same way S.A. teams are, many that are in the European football lexicon now wouldn't be so revered even though their talent was the exact same.