Judaism needs people within the faith who are capable of and disposed to interacting with ha goyim. We as a people cannot, either practically or (in the context of our assigned role on Earth) morally withdraw from the world around us.
We can certainly have groups or kehillim who can and should do so. Our strength, I believe, lies in our diversity, and such communities are part of our mantle; there will always be among us souls of profound tenderness who can only thrive in places of refuge from the conflicts within the world.
But to survive as a people, as an am, we will need men and women of great faith who can still serve as our interface to the other nations of the world on at least partially common ground. Others need not believe what we believe, but they must know the truth about our beliefs and why we hold to them, not the lies that others might manufacture in our absence.