Nothing is getting done because the Repubs are stonewalling almost all legislation.

This article (from today's Washington Monthly) sums it up nicely.
Link

Today's New York Times explains Mitch McConnell's "nyet" strategy for making sure that nothing gets done:

Mr. McConnell and his fellow Republicans are playing such tight defense, blocking nearly every bill proposed by the slim Democratic majority that they are increasingly able to dictate what they want, much to the dismay of the majority leader, Senator Harry Reid of Nevada, and frustrated Democrats in the House.

In fact, the Senate Republicans are so accustomed to blocking measures that when the Democrats finally agreed last week to their demands on a bill to repair the alternative minimum tax, the Republicans still objected, briefly blocking the version of the bill that they wanted before scrambling to approve it later.

Italics mine. It's hard to say anything about this other than the obvious: the Democrats have a very slim majority; the rules of the Senate work against them; and the Republican Party, even as it prepares to shuffle into what may well be a decade of irrelevance, continues to display a genuinely remarkable ancien régime ability to stick together and insist that nothing is wrong until its collective face turns blue. Even the fact that the entire country may well turn blue next November as a result doesn't dissuade them.