While the Federal Reserve can pump more money into the system this risks losses on the securities they hold in return for this cash. In addition, quantitative easing no longer has the same surprise impact; reducing mortgage interest rates at the margin has little impact on households facing unemployment and unable to sell their own home.
Think of the economic environment of several months ago, prior to the more recent financial turmoil. The appearance of these sorts of benign indicators could have provided useful testimony in support of the end-of-history thesis in the economic realm. But then what is to  1  Francis Fukuyama advanced an affirmative view of this question when he published "The End of History?"