Because ...? Other than "they're old" there's no actual reason you'd think this. Their "old" guys are still performing at an elite rate and while it's early, they've gotten off to a really strong start. On top of that, they improved their defense corps tremendously with the addition of Petry and Ruutta over Matheson and Marino.
Not to belabor the point but you're not really giving reasons for why a 100+ point team the past handful of years is suddenly going to miss this year because it's certainly not based on on-ice performance or depth of roster.