They could easily pick some of the best prospects of South America since the club is very respected in the region. At some point they would find some gem without paying too much. But i think they have some specific policy against signing straight from South America.
Yeah we tried that in the 00s and it didn't work out. Missed out on the likes of Aguero ("not good enough") while signing Ernesto Sosa, Breno, etc. After that i remember Hoeneß saying that we are not signing/importing any South America talent again.
edit: But i must admit this is not too bad, because many young South Americans have problems adapt to german mentality, weather and language. We have to focuse on talent in our reach from Germany, France, Netherlands and Belgium. But somehow we totally overlooked talent from Belgium. But we obviously go for the french now (Coman, Tolisso, Pavard, Hernandez, ...)