Had to stop up and think for a moment but you are absolutely right about that. Great prospect pools come from having elite talent, but if your elite talent doesn't translate pretty quickly then something has probably gone wrong. Arizona had a top prospect pool for quite a few years, but that was in large part due to Strome never quite taking the step. It's not like their situation was better than ours just because Marner was an instant hit and Strome took until now to become valuable.
If you map out a basic cap and roster management preliminary plan, I think it would look something like this:
18/19
Gardiner -> Dermott -> Rosén (Gardiner's spot is taken by Dermott, and his spot is taken by Rosén)
Zaitsev -> Liljegren
Hainsey -> Ozhiganov
Lindholm -> Moore
Brown -> Bracco
Extended = Johnsson, Kapanen, Marner
19/20
Muzzin -> Dermott -> Sandin
Marleau -> Moore -> ?
Gauthier -> ?
Extended = Dermott
20/21
Andersen -> Woll/Scott (Hopefully)
Extended = Liljegren, Sandin, Hyman, Rosén
21/22
Kadri -> Nylander -> Bracco -> ?
Extended = Rielly
Goaltending is the big question mark. Who knows how our situation will look in a couple of years. I'd preferably like to avoid giving a long-term contract to an aging goaltender though. Other than that, we only really have a couple of question marks in depth positions. Unless Bracco can't translate into the NHL, in which case we might miss a top nine RW or a third line center, depending on what we do with Willy.
So while our farm is getting a bit thin, we're young enough with the right kind of pieces that we should be fine over the foreseeable future. It likely won't be this easy though, things always go wrong at some point.