From a simply view I guess two things must happen to get to the GS predicted price level. Either demand for the I/O must fall or supply must increase, driving down the price.
Mr. Ken Brinsden, MD of Atlas Ltd. in a presentation that was posted on HC by GlenStewart20 on 27 Dec. 2012 (Post: 8920735) at a Sydney Mining Club commented on the disparity of Chinese I/O costs, see slide 12 at