The reality -- QB performance is the difference maker.
A team will not be successful in the 'tournament' unless they have a solid playoff proven QB at the helm.
For instance, the Texans in 2015 had a stellar top-notch top-ranked defense.
But, in the playoffs the Texans with Brian Hoyer got smoked because they lacked quality playoff-caliber QB play.
Even the Jets in 2015 had an exceptional defense but their QB play destroyed any shot of them getting into the playoffs and winning playoff games.
(Also in 2014, Arizona Cardinals had a quality defense but in the playoffs they had Ryan Lindley starting as the QB and, they lost to Carolina).
In the playoffs, teams are for the most part evenly-match, and the coaching staff that prepares and makes quality in-game adjustments usually win.
In the playoffs, winning teams know out to take advantage of one-on-one match-ups and winning teams have QB's that commit the least/dumb mistakes and conversely convert crucial pass completions.
In last years super bowl, if Pete Carroll and by extension Russell Wilson decided to run the ball with Lynch at the goal line and in this year's super bowl, if Ron Rivera and by extension Cam Newton decided to max-protect at the line of scrimmage and double-team Miller and/or Ware, maybe the outcome for each Super Bowl would have been different.
At the end of the day, unless the team performs with quality QB play and very smart coaching, emphasizing simply defensive pressure is simply NOT seeing 'the forest for the trees' when determining playoff & Super Bowl success.
Dallas make the smart overall team decision and rebuild.
Begin with drafting Wentz or Goff.