According to Goldstein, for what reason do the three superpowers prefer continuous warfare to peace?

You can find this answer in book 2, chapter 9. An excerpt
of Goldstein's book is provided. Within that excert, chapter 3 in entitled "War is
Peace". It establishes the reasoning for maintaining wartime as opposed to
peace.

For each of the superpowers, they have come to the
realization that war achieves several means. First and most important, it uses up the
surplus of goods produced by the people. This helps maintain a controlled society
because if some people began to use more goods than others or rationing was done away
with, wealth would occur for some. This would certainly disrupt the order. Without a
lower class, Big Brother and the other government hierarchies have no one who needs and
depends on them therefore remaining subject to them.

The
basis of war is acceptable to people. It is something they have lived with. To the
governments, it gives the people a reason to fear, they fear something else, never their
own government. It also helps them place their hate. People will hate. This is a way to
control where that goes.