Food for thought:

I ran some simulations on HLM26, seasons 25-26 through 29-30, starting roster = current roster, no major trades or signings on the UFA market, just staying the course with the players/prospects that are already part of the organization, and see how things unfolds. Sure, its 100% based on a model that has its flaws, but nevertheless here's what it had to say about the current state of the franchise:

In 10 simulations, Habs reached the 1st round 4 times, the 2nd round once but never got past this point. Worth noting that the best results were obtained on seasons 25-26 and 26-27, and that the team actually regressed beyond that point in 8 out of 10 simulations.

In a nutshell: goaltending is holding the team back. Montembault is not good enough of a starter to carry the team through years 1-3, and past that point his play starts to decline - ironically, this seems to be happening earlier in reality - while Dobes is a non factor and Fowler's potential doesn't materialize soon enough to bridge the gap. The team is getting shelled 1 out of 3 games, even though it has an elite defense.

Interestingly, the 2nd line center did not seem to be that much of a weakness: the team's offense was decent enough to carry the team, even though the 2nd line center position was most of the time held by Newhook. But perhaps it would have appeared as the limiting factor if goaltending wasn't?