Some of the prospects traded by DD got hurt, and that is something very hard to predict.
We will never know just how good Anderson Espinoza might have been. I thought, at the time, he was an overpay for Pomeranz, but maybe due to his injury, the trade looks fine, now.
It does seem pretty amazing that DD traded about 20 players that were or once were top 20 prospects on the Sox rankings lits. The ones he kept have done way better. Call it mostly luck or happenstance, but it is true.
In hindsight, those who said he "emptied the farm" turned out to be wrong, despite the sheer number of prospects dealt away.