Why would Arizona make that trade?

Malkin doesn't make them cup contenders, and that's a thunderous amount of assets - particularly considering they could probably get Duchene+ with those same assets.

Arizona would make that trade because it would be an insanely good value to get one of the most prolific scorers in the game (plus a nice depth player in Wilson). When 71 is dialed in (like he has been for the past few weeks) he is as good as anyone in the NHL, Sid included. I mean, the guy has a legit shot at the Art Ross this year even though he missed a decent sized chunk of games. Over point per game every single season in his entire career except for the year he tore his MCL & ACL. I'm seriously curious what the logic is behind "Duchene is more valuable than Malkin"

Yeah, that part is ridiculous.
I seriously doubt if those trades actually make the Pens better. I'd rather have Malkin+Wilson than Duchene+Eakin. McGinn is not much of an upgrade over any of our youngsters, Rieder is nice though. On the back end 3d pairing Maatta-Hainsey would be muuuch better than Chychrun-Johns from contending point of view, although your option is defenitely great in the long run

This was more or less done with the opening for winning Cups is getting smaller with the current core. That 1st round pick from AR is the closest they will get anytime soon and while not a guarantee to be a home run, gives them the best shot to replace Geno/Sid for the long term. Eakin is locked up with a friendly deal for a few years giving time for Sundqvist/Guntzel to develop down the middle. Duchene is valuable for the versatility on LW or C.