The chooks lost a very aggressive player in Luke O'Donnell, who was on one leg, but it is the attitude that he brought to their team and in particular pack. Now is it a surprise that they are now struggling for consistency.
It has nothing to do with race, but all to do with culture and attitude.
Example A. Is it any surprise that probably the best and most consistent player of Islander descent to ever play is Petero Civoniceva who if I had to guess growing up in QLD in the time he did, there would not have been the same amount of Islanders as there are now. Therefore he would of had to assimilate moreso into the Aussie culture, which in turn gave him a different mindset and attitude.
Look it will change over time for the islanders, the more they assimilate the more they will become mentally toughened like the European players, but it will take a generation or so.
Example B. Why do on average Asians do better then Europeans at Maths and the Science's? Not because they are superior humans or have better brains then the rest of us, but because of the way they are driven through culture and attitudes.
People might not like the politically incorrect truth, but cultures are different which does NOT mean they are any better or worse then any other. It may mean though that a specific attitude or culture is less suited to professional sport from a consistency point of view. But again let me make myself clear, it can an will change with more exposure and all humans are equal no matter what race. Players like Petero and Jeremy Smith are prime examples of that. Players like Frank-Paul Nu'uausala and Joseph Paulo are of the opposite kind.