Adriano is the best example of a phenomenon in Brazilians of lack of longevity - whether it is because of bad mentorship, additional pressures or poor decisions (e.g. why did Oscar go to China at 26?)
Many of these players just didn't fulfil any expectations: Most expensive player ever Denilson who ended up in Saudi Arabia just a few years after he went to Betis, The ever-injured Pato, Diego (discipline problems the whole time), Elano (assaulted his indian club owner in Goa) and the other ones who came to england with lots of hype but didnt do anything - Robinhoe, Anderson, younger Denilson etc...