Since when? Maybe that was the plan going into 2017, but you can't assume a guy will suddenly turn his stuff into gold.
This seems to be old White Sox fan logic going to work, because even just a few years back, we were incapable of doing anything but relying on a select few guys to translate their potential into tangible results. That isn't the case anymore. We have quantity as well as quality, so we can accommodate for the inevitable bust here or there that ultimately takes place, regardless of franchise.
Fact is that there were very legitimate doubts that Giolito could be a consistent rotation pitcher since he was dealt. He was a high risk, high reward guy. He had a ton of potential but a lot of issues to adjust. So far, those issues are still a factor and we aren't reaping his potential. Granted, he's been better, but not good at all still.
You can't expect the plan moving forward to be relying on a guy who was a flight risk going into the trade.
As for what Hahn said, I couldn't care less. I need context first, and more often than not, that will just be GM speak, because what purpose does it serve to talk down a guy in your current rotation? Either you hurt his confidence or your hurt his trade value or both.