Because it was designed to fail.
If the Congress had wanted to get the debt problem solved, it would have voted for “failure sanctions” with sharp teeth.
What are the negative sanctions for failing to come to an agreement? Few people remember. Do you?
Here is what will take place if the supercommittee fails to come up with a plan: a $120 billion a year cut in spending over 10 years, beginning in January 2013. That means $1.2 trillion, total.
What is the estimated increase in the U.S. government’s debt over 10 years? Over 10 trillion dollars — $975 trillion through 2020. (No government agency is projecting to 2023.)
In short, the proposed cuts and window dressing. They are duct tape on the iceberg side of the Titanic.
As for the law, it can be changed at any time.
In other words, the entire idea of the Supercommittee was a sham to placate Tea Party Congressmen. Congress had no intention of cutting spending or putting a cap on the debt. Congress wanted to get Tea Party voters to shut up and stop pressuring the House to cut spending.
The Tea Party voters back home did stop pressuring Congress. But they will be back next November. We will see then if they have the votes to elect politicians with enough votes and enough willpower to make the necessary cuts.

what is tat>??
very well indeed