Yes, it is true that one of the great advantages that Portuguese clubs like Porto and even have it had was the fact that they could buy South American players at a low price and could yield them later as the case of Falcon, James Rodriguez, Anderson and others.
In the case of Porto in 2004 he was able to monetize several Portuguese players such as Ricardo Carvalho, Nuno Valente, Maniche among others because at the time these players were in lower expression clubs in Portugal.
I remember that at the time EPL and La Liga were more restricted to extra community players and giving the work visa this made these players have to enter Europe via Portugal that they had less restricted rules.
However, as now, EPL clubs and even La Liga will directly buy players from Brazil and very young with Stephen's case for Chelsea and Endrick for Real Madrid hired even before they are old enough to leave the country.
At this moment the Portuguese clubs have to reinvent themselves, in my opinion, with their formation as the case of Vitinha, João Neves, Nuno Mendes, Diogo Jota, etc.
!BBH
RE: FC Porto: A Detailed Analysis of the Decline and the Way Forward