Because Harry Reid doesn't have the balls to make the hard calls.
The Senate has already voted on, and rejected, the House's budget proposal.
Meanwhile, we haven't had a budget passed in 3 years, no balanced budget, no pay back of the crushing debt, $15 trillion in debt and rising, and continuing resolutions that don't address or fix the problem.
So, a pox on everyone's house, in that case? Since the Republicans haven't proposed any plan to balance the budget (Romney's plan leaves a deficit of around 800 billion a year, and the Ryan plan doesn't balance the budget until 30 years out (and even that's built on a lot of bullshit claims)).