From the responses in this thread, you can see that even amongst Celtics fans, our young guys are not valued enough to trade for legitimate vet all-star type players. In my opinion, Sullinger and Smart have all-star talent, but that is far from the view in here, never mind in the league in general. Considering that is the case, we won't get good enough return for them to trade them. Never mind KO, even Ainge called him a role player when he drafted him.
For example, just look at the Kevin Love trade. Not once were our assets ever considered as a top 3 offer, and that had nothing to do with Lebron. Minnesota wanted Wiggins, who is far from a sure thing IMO, much more than a combo of Sullinger/KO Plus #5 pick.