I'm not saying they aren't first round value but there's a difference between a first round pick value and a proven star commodity. I can't even say Anaheim would be looking for first overall pick returns because 1OA's have missed in the past. For example, if I'm Anaheim I wouldn't trade Gibson for Hischier, Hughes, Ekblad (maybe if a capable goalie comes back too), RNH, or even Hall really. Yakupov should go without saying. That's not to say all those guys are misses, but some like Ek and Hall aren't enough to make trading your best player for the future worth it with no one to replace him at the most limited position on a team's roster.
But take all those names together and that's more than half of the last decade's worth of 1OA's. Now I'm not stupid, I know there have been some very good picks made beyond 1OA with some real superstar players, but the draft history shows the further you get away from the top 5 picks, the less likely a selection is to have an above average NHL career.
So continuing to beat the drum on the concept of 1st overall equivalent pieces is a pretty flat argument in my opinion. If someone came in here and said hey how about Griffen Reinhart, Micheal McLeod, Lawson Crouse, and Samuel Morin for John Gibson? That person could say, "hey not only were they four first round picks, but top 15 picks to boot!" but that wouldn't really make that package of crap worth an elite goaltender would it? I'm not saying MMC's proposed package is on that level, but the fact that the assets equate to four first rounders really doesn't matter if all the proposed assets don't pan out to a high enough improvement to the Ducks roster to offset the loss of a top ten, arguably top 5 goaltending talent in the NHL who is still very young for his position and signed to one of the more manageable contracts you could ask of an elite goaltending talent.
And that's all before you get to the notion that Anaheim doesn't have to, and really isn't in a great position of strength to be trading a guy like Gibson. Miller basically has 1 maybe 2 more years left in him. Dostal is proving to be a fantastic goaltending prospect but has no pedigree on the North American stage to really give Anaheim a cushion to put their starting goalie on the block. So, considering Gibson is far from expendable and is, rather, their most untouchable player, it would take an offer that so very clearly improves the team enough to offset the loss of elite talent in net to make the team even entertain the idea. A package of futures, even above average in quality ones isn't gonna get you there if the team can't be certain what they're getting in the long run. It's not an indictment on the players in question. It's a matter of having a guy who's about as good as you could reasonably hope for at his position, who you can build a team around, and throwing that certainty to the wind in exchange for unproven potential. There's no real reason for Anaheim to gamble so why should they?
You say no team in the league would give up more than the offer in question for an elite goalie as though the question at hand is "what can Anaheim get for Gibson" rather than what it actually is which was "what would it take for Carolina to get Gibson." Just because you think an overpay is improper value doesn't mean that's not what it would take. The guy is virtually untouchable. You want to pry him out of Anaheim, the only realm where that could happen is one where an entirely implausible offer is going back to Anaheim. I should think that should resolve the question.
And it's almost certain that barring some ridiculous overpay, neither would Anaheim's management. To put it in a more simple way to understand, Gibson is Anaheim's Aho, Dahlin, McDrai, etc. Typically franchise cornerstones don't get traded out unless the team is in a bind or there's behind the scenes drama for anything less than a king's ransom. We exist in an era where franchise players are increasingly staying long term with their teams. With Getzlaf's decline, Gibson is unquestionably the team's franchise player and it would take a lot for the Ducks to part with him. Again, you're being dismissive about the whims of Ducks fans as though Carolina convincing Anaheim to part with Gibson would take anything less than an offer that exists outside the realm of plausibility. It's not Ducks fans saying they don't want to trade Gibson. They're saying Anaheim wouldn't want to because they don't have any reason to.