This is the thing with Foreign coaches (IMHO), they are there to do a pre defined job. Be it qualify, make the finals, or win the WC, that's all they want to focus on. Development is not a part of their agenda.
The Socceroos are a prime example. A string of good, foreign coaches got us to successive WC's for the first time since '74, but we had an extraordinary good side (by Oz standards). We now have an Aussie coach who isn't looking to make an impression at this WC, he's looking to develop a side for the next one. He's gone for youth & Tim Cahill is one of the few players from the 2006 campaign left in the side.