Good football (or other sports) teams are always winning or loosing together. When you listen to interviews a team player always says that the team together has won or lost. Never would he or she blame one single player in the team when a game was lost. Never would a good teamplayer mention that the team won because of him- or herself. This demonstrates the team spirit and this is exactly what separates high from low performing teams. When a game is lost there is no way to change the fact, but it is possible to improve for the future by not blaming a team player because he or she made a mistake or was not performing enough. This only makes the team weaker.
Unfortunately I exactly see too many times this "finger-pointing" mentality. There is more effort to find somebody else to blame than to rethink the way we are working together or we can improve the team as a whole. In such an environment people are tending to go into protection mode. This means that on the one side they are collecting and archiving evidence for both, their correctness and mistakes of the others.
Easily to imaging how much effort is used to act in such an environment. Not only that there will be never a thing such as team spirit, the members also spend half of their time to protect themselves to be attacked. The performance is of cause very low.
To bring back the team to speed is not easy, especially when such a behaviour is tolerated by the leadership team. The radical (and possibly the best solution) is to get rid of some leaders and hire or find leaders that are focussing more on teamspirit where making mistakes is not a crime but a result of going new ways beyond the limits.