And since they can't be simply be traded right away because the Nets wants more, and you can't blame them. Again, it boils down on the money they put in the line and they want something in return, like future draft picks, because that's what the lost as well when they sign the 2.
Money is not a problem since once Kevin Durant is traded, the contract offered by the Brooklyn Nets to him will be voided at some point.
The Nets is asking for a much good trading package because Durant is a big name and offering future draft picks can't satisfy them since, in the first place, they already gave up their future picks when they sign Durant and Irving.
As much as possible, they like a set of players that are as worthy as Durant's playing skills. But if they keep on insisting more, they will have a hard time trading him and they might end up a not worthy trade in return.