I think this is where the argument that 'the Bledisloe is the pinnacle of our game' comes in. Players should rate winning the Bledisloe as more important than the World Cup. Rugby's version of State of Origin i suppose.
Well, for any of our current players winning the Bledisloe Cup and winning the Rugby World Cup are both things that none of them have experienced.
The only thing they can more directly control is participating in those things. Players generally participate in far more Bledisloe Cup contests because we contest it every year than Rugby World Cups so it isn't really surprising that they base important career decisions around trying to go to a RWC.