I don't think it's helpful to keep thinking that the Jets should get trade value for what Hellebuyck and Scheifele have been, instead of what they'll be in the future (performance and salary). The Jets have already received substantial value from both players over the past several years. Now, they need to get what they can in trade value and move forward, even if it's for rental prices, just as they did with Ladd and Trouba and Copp. Of course the Jets could have gotten much more trade value a few years ago for both, but then they wouldn't have them at good value for those years.
For the Jets, the positive is that they have gotten the best years at the best contract values for core players, and their next team will get less value.
So Chevy's job is to get the best value possible at the most opportune time, and not worry too much if critics compare trade value to what they would have fetched previously.