I am fully aware reasons why we lost each playoff game. But one thing I've noticed when these discussions come up is there are 2 lists depending upon the poster. It's either A. Everyone's issues but Romo's or B. Romo's issues. I still haven't found anyone who will simply list ALL of the reasons we lose each game. It seems everyone wants to boil it down to a few key moments (e.g. Crayton drop pass, Murray fumble) or a high level issue (defense sucked or offensive line sucked).
So my guess is that you would like to point out reasons that don't including Romo for why we lost those important games until you're blue in the face. And your reasons wouldn't be invalid. It would just be incomplete.
I don't quite view it that way.
I've recently watched some of our playoff games from the 1970s, and there are things that Staubach did in some of those games (missing open receivers, etc.) that could have cost the team if not for the running game or the defense. (Some of those were pretty poor performances by him.) In games that we lost, there were things that Staubach did that would have been good enough to win if not for defensive failures or mistakes by other players. However, there may also have been a play here or there that contributed to the loss.
The tendency is too put too much blame or credit on the quarterback. Are there things in the playoff games that Romo (or Staubach or name your quarterback) could have done better? Absolutely.
When you lose, every bad play (every stray pass, sack, defensive lapse, etc.) becomes a big deal because it's possible that one of those things going right could have made the difference. When you win, those bad plays don't matter. There are rarely any games, win or lose, where the quarterback is perfect. So if it's a loss, naturally any imperfection is going to be seen as contributing to the loss and for some, is going to be blown out of proportion.
So I guess to answer your question: Yes, since one play could have been the difference between winning and losing in several of our games, then Romo contributed to the losses. However, he also was one of the main reasons those games were close IMO and if other players on the team had played at his level, we would likely have won a Super Bowl title. Again, I cannot prove that but it is what I believe based on observation.
Going back to Staubach as an example. One of his great playoff comebacks was against Minnesota in 1975, part of what earned him the nickname "Captain Comeback." However, if the defense had not held the Vikings to 14 points, the focus would have been on the offensive failures, even by Staubach, instead of that comeback he led. He missed on some plays he should have made, but the defense kept Dallas from paying for it changing how fans view his play in that game.
This is the way of the game. No player is perfect so there's always going to be blame for them to share in a loss. Sometimes a player deserves an inordinate amount of the blame, but often it's the fact that the team couldn't afford to make one mistake that makes one mistake stick out more than it should.