I don't see what any of that has to do with scoring goals.
What's the excuse for the Calgary series?
The top lines often get locked down in the playoffs, so it becomes up to secondary scoring to make up the difference.
Take a look at what's happening in the SCF.
Patrick Kane: 5 GP, 0 Goals, 1 Assist, -1
Jonathan Toews: 5 GP, 1 Goal, 2 Assists, +2
Steven Stamkos: 5 GP, 0 Goals, 1 Assist, -1
Tyler Johnson: 5 GP, 1 Goal, 1 Assist, +1
Toews may go down in history as one of the greatest playoff leaders and winners in NHL history, and his current PPG in Finals games is 0.65 PPG, which I believe is a level that you considered quite mediocre when talking about expectations for the Sedins before.
Here's playoff production from 2008 onwards (after the Naslund era)
Kane: 0.97 PPG
Henrik: 0.94 PPG
Daniel: 0.90 PPG
Toews: 0.88 PPG
Kopitar: 0.86 PPG
The reality is that the Sedins have produced in-line offensively with many other top players in the playoffs, but the Canucks haven't had the same offensive and defensive depth as the championship teams. The Kings and Blackhawks can have their top offensive players average 0.9 PPG in the playoffs (and less during the SCF) and walk away with 4 (and maybe 5) championships. The Canucks get bounced in the first or second round most of the time instead.