Problem is Fedde should be a non-starter for Hahn. The Sox have already created a huge stockpile of arms by trade and drafting. They need to make sure they are getting position players back from these next few trades.
I get what you are saying about value and how it can disappear. It can also increase for a player like Robertson if he continues to show he is back to full health, which would only increase his return.
That being said, if I am Hahn and The Nats offered Soto and a couple more prospects, I may be willing to step back from my Robles demand.
"Always look on the bright side of life!"
Eric Idle