When exactly was it that the U.S. became a can't-do society?

From NYTimes.com: Yes We Can

Mr. Gore's focus is primarily on solar, wind and geothermal energy. His belief is that a dramatic, wholesale transition to these abundant and renewable sources of energy is not just doable, but essential.

My view of Mr. Gore's passionate engagement with some of the biggest issues of our time is that he is offering us the kind of vision and sense of urgency that has been so lacking in the presidential campaigns. But the tendency in a society that is skeptical, if not phobic, about anything progressive has been to dismiss his large ideas and wise counsel, as George H. W. Bush once did by deriding him as "ozone man."

The naysayers will tell you that once again Al Gore is dreaming, that the costs of his visionary energy challenge are too high, the technological obstacles too tough, the timeline too short and the political lift much too heavy.
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When exactly was it that the U.S. became a can't-do society? It wasn't at the very beginning when 13 ragamuffin colonies went to war against the world's mightiest empire. It wasn't during World War II when Japan and Nazi Germany had to be fought simultaneously. It wasn't in the postwar period that gave us the Marshall Plan and a robust G.I. Bill and the interstate highway system and the space program and the civil rights movement and the women's movement and the greatest society the world had ever known.

Bob Herbert has hit the nail on the head with this insightful op-ed piece.  What happened to having goals and striving to accomplish them?  I feel like we've adopted a siege mentality to all things.  This has to change.