We already know it was a win for the Bears. We won’t know if it’s also a win for the Raiders until we see how the draft picks they get pan out.
Not really though. It is already a "win" for the Raiders in the haul of draft capital alone as long as the draft holds up as one that produces quality players in any average NFL draft excluding the outlying crappy years where no GM anywhere had much of a chance at all.
They obviously went from elite pass rushing to below average (I don't know their pass rush stats post Mack but I know it wasn't good).
Their move will be to get to elite in some area through the draft capital. It doesn't look like they will get back to elite at pass rusher but
theoretically if they used their extra 1st round and 2nd round picks to draft the next Greg Olsen, Drew Brees, and Antonio Brown with their picks, they would have little to no sellers' remorse due to the explosion factor on offense. And one would think they HAVE to believe they can and will do something similar.
Whether they succeed in making the right picks is a commentary on their scouting
including the scouts telling them BEFORE the Mack trade what will be there in the draft in terms of return on trade investment.
If the picks fail, it may not exactly be a commentary on the trade details but on the scouting department that informed them as to the potential of this upcoming draft.
(PS I already suspect the scouts are going to fail them due to scouts being historically unreliable in projection and due to the fact that Gruden noted he picked the Bears because he looked at our roster and thought Mack would make the least impact in Chicago than New York or Buffalo in terms of record turnaround. This seems objectively misguided. Even back in August, my normally pessimistic self CELEBRATED Mack and what that means for our record coming up).