Our biggest issue with trading with the Islanders is that they couldn't offer the main piece we wanted in return for Duchene, a young top pairing potential LD. So I'm sure they put in a good offer in a vacuum, but the need probably wasn't as close as it could've been.
And that's fair, but I can't see a team that has what the Avs are looking for willing to deal for Duchene. Now, this isn't at all to say that Duchene isn't a great player or that he's worth a good return, it's just that there are very few teams that fit Sakic's criteria for trade partners. Most teams who have blue-chip D prospects most likely aren't looking for someone like Duchene because they are pretty far from contention and could potentially lose Duchene via trade of free agency before their contention window even opens.
Other teams that would want Duchene are most likely the contenders (i.e. Pitt, Chicago etc.) but they most likely don't have the requisite parts that the Avs desire due to years of mid to late draft picks and are most likely under a cap-crunch.
That leaves you with middling teams like MTL, NYI and OTT whom aren't perfect fits, but are capable of providing great returns. The issue here is that these teams are aware of the lack of potential suitors and don't want to offer up the Sergachev's, Chabot's or Barzal's of the world.
I also personally think that Sakic killed any chance of a deal with the Islanders going forward (much to my chagrin as I really think Duchene can make the Isles extremely good) by seemingly turning down an offer from Snow that met his asking price and I would assume asked for more, which ultimately Snow balked to.
Who knows, so much can change, but this is just my opinion.