They simply didn't 'constantly lose games they had wont he last 10 years for many reasons.' Garrett's Cowboys pretty much beat the teams they were supposed to beat, and lost to the teams they were supposed to lose two. And were pretty much .500 against the teams as good as they were. It's been pointed out, many times, that they don't get blown out. They're in just about every game.
You just can't get around the idea that you thought those 8-8 rosters were rosters that should have been contending for titles when they were really rosters that were contending for the division only. And then, when our .500 teams lost half there games, everybody was running around here saying the problem was with the play calling, citing plays that didn't work and suggesting the opposite play calls would have. The whole, 'hindsight 20/20' thing.
The reality was, we were rebuilding the offense and had a great QB and a terrible defense, and as they team got better players, they started winning more. Saying that, they're still ~25% in the league under Garrett in terms of wins.
The playoff games were us getting beat by comparable teams in games we could have won. The Seahawks playoff game was in 2006, under Parcels, and before Garrett got here. *That* was a game we should have won, and a game where we coached too conservatively given all of their secondary injuries, btw.