An intriguing graph from Brad DeLong.

In other words, slower or negative economic growth and higher unemployment now leads to faster growth later.

The CEA also notes that the deeper the recession, the greater the recovery.

However, the analysis does not include pre-WWII data.  The causes of our current decline is most similar to the 1930s. 

But even including the 1930s, American growth does snap back to trend.

I see no reason to think that this trend is structurally broken.