Even Jerry and his yes men (largely McClay) have put the Cowboys in position for a serious post season run. Consider...
#1 Seed in the NFC in 2007. Great offense, meh defense. Lost to the Giants at home in the first (divisional) playoff game, a game they should have won, but can't pin that on Jerrah. They did put the team in position. Not sure they would have beaten New England in the SB that year though. Matter of fact, I'm gonna say no. TB never lost to Dallas during his tenure in New England.
Divisional round teams in 2009 and 2014, both losses on the road. Although they coulda beat Green Bay in that divisional game (Dez Bryant 'no catch'). Again, good, competitive team that didn't finish. Is that Jerry's fault?
Now...2016...this is the one that hurts. Clearly the best team in the NFC in my opinion. Loses to A Aron and the Pack in the divisional round. Could have beaten Denver in the SB that year, IMO. Again...personnel wise...team was in position, then *poof*.
So in 17 years, two #1 seeds in the NFC, at least 4-5 other playoff teams that made it to the divisional round. Not a bad 17 year run. But of course, they didn't win the big one, nor even got to the NFCC game.