The biggest issue? The Cowboys have no clue how to win.
It hasn't always been like this.
Remember the time the Cowboys scored 11 points in the last 20 seconds to beat Buffalo in 2007 and, a few weeks later, when they scored two touchdowns in the final minutes to beat Detroit 28-27?
Those represent the good old days.
We're talking about a team that's 4-11 in its past 15 games decided by a touchdown or less. Jason Garrett's four losses have been by a total of 10 points.
Until the Cowboys -- not just Romo -- figure it out, losses like Sunday's debacle against the New York Jets will continue to be the norm. Look at some of the creative ways this team has lost games since the start of last season:
• Alex Barron's holding penalty negated a touchdown on the game's final play in a 13-7 loss to Washington.
• Roy Williams fumbled at the end of a 47-yard catch-and-run that should have led to the game-clinching points against New Orleans. Instead, the Saints drove 89 yards for the winning touchdown with 1:55 left.
On Sunday, the Jets rallied from a two-touchdown deficit to beat the Cowboys, who had been 246-0-1 with a 14-point lead in the fourth quarter.
Garrett must confront the issue and make sure his players learn from their mistakes before this team has any hope of ending its futility at winning time.
The fourth-quarter failures aren't about bad luck. They certainly aren't about a lack of talent or a quality quarterback fans believe chokes in the fourth quarter.
So much of professional sports revolves around confidence. Some teams consistently find ways to win, while others consistently find ways to lose.
This is why Garrett spends countless hours talking about filling the roster with the right kinds of guys and the importance of mental toughness. You can't win in the NFL with mentally soft players because they wilt under pressure.
Opponents outscored the Cowboys 126-111 in the fourth quarter last season. The Jets outscored Dallas 17-7 in the fourth quarter Sunday.
We can blame much of the collapse on Romo, who fumbled at the New York 2 and threw an interception in the fourth quarter when he made a dumb decision to throw at Darrelle Revis.
But we also can blame Jason Witten for not running over the safety, who pushed him out of bounds at the New York 3, at the end of his 67-yard catch-and-run.
And we can blame the offensive line's inability to create enough push for Tashard Choice to convert a third-and-1. And we certainly can blame the punt team for the miscommunication that resulted in a blocked punt that was returned for a touchdown, tying the score at 24.
See, it wasn't just Romo.
"There's probably a development that teams have to go through, just like there's development players have to go through," Garrett said. "Sometimes it happens quicker for certain players and certain teams, and sometimes it's a longer process.
"Understanding how you persevere through adversity and learn from it and benefit from those negative and positive experiences helps. It has probably happened a lot of different ways for a lot of different teams."
Romo insists he will learn from the mistakes he made against the Jets. Pray he does. Still, Romo absolutely must play better in the fourth quarter, like he used to do.
From 2006 to '08, Romo completed 67.1 percent of his passes with 11 touchdowns, four interceptions and a passer rating of 113.2 in the fourth quarter with Dallas ahead or behind by a touchdown, and the Cowboys went 30-15.
Since then, Romo has completed 55.8 percent of his passes with six touchdowns, five interceptions and an 82.6 passer rating in the fourth quarter with Dallas ahead or behind by a touchdown, and the Cowboys are 12-11 in those games.
It's OK to trust Garrett because, thus far, he says and does the right things, such as the game situations the Cowboys are forever simulating. Teams develop poise because they're prepared.
He hired the NFL's best strength coach, so the Cowboys shouldn't become slaves to fourth-quarter fatigue as we move deeper into the season.
Right now, the Cowboys enter games hoping they can win or believing they can win.
Until Garrett transforms their attitude and they expect to win, the Cowboys and Romo will continue to fall apart in the fourth quarter.
Jean-Jacques Taylor is a columnist for ESPNDallas.com.