Some further thoughts based on readers' comments on my original post, and other recent articles:
It's true that funding agencies do tend to stress low-risk projects, but this approach makes sense. Scientific achievements most often come from slow and steady progress, punctuated by an occasional major discovery. The major discoveries can't occur in a vacuum; they rely on having that foundation of knowledge that was built up over prior years.
You're right that important work often is the result of cumulative efforts. The cult of paradigm-breaking, revolutionary science dismayed even Thomas Kuhn, whose Structure of Scientific Revolutions became of the best selling scholarly books of all time. On the other hand, my own friends and acquaintances in science seem to agree with the poll results that there's too much caution in grants. That may be true in journal editing, too, and not just in the US. The Spanish physicist Juan Miguel Campanario has studied the rejection of high quality papers.
I agree with Umesh Patil that scientific quality can have a long lag time. I should add that I hope the Pew Research Center will follow up with a survey focusing on what's happening at the graduate and postgraduate level now. It might also look at the controversy over opportunities for scientists and where there is really a shortage:
Among the most vocal critics: Michael Teitelbaum of the Alfred P. Sloan Foundation in New York, which funds basic scientific, economic and civic research. He says there are "substantially more scientists and engineers" graduating from the USA's universities than can find attractive jobs.
"Indeed, science and engineering careers in the U.S. appear to be relatively unattractive" compared with other career paths, he told Congress in 2007.
The Sloan Foundation sponsors some of the most prestigious fellowships for young scientists, so their assessment of scientific opportunity should be cause for concern, even though the Obama administration doesn't share it. Last year Dr. Bruce Rosen of Massachusetts General Hospital told the Boston Globe:
"It is a time of great difficulty, in my own experience not seen since the mid-late '80's," he said. "In our own lab I've begun to see very promising young scientists choosing careers in business consulting rather than research positions, and am facing the very real possibility for the first time in a very long while of watching good scientists potentially lose their jobs for lack of support. This is obviously devastating for the individuals involved, and very dispiriting to the community of their peers who see themselves sometimes only a small step ahead."
According to this article in Nature (full text may require subscription) there are significantly more principal NIH investigators over 70 than under 30:
"We're eating our seedcorn," says [NIH Director Elias] Zerhouni.
Anna raises this issue from her own experience as a young investigator and also questions conventional scorekeeping on scientific prowess:
I don't understand why US eminence is an issue - as if we were in competition with everyone else, which doesn't seem to be the spirit of science. Haven't all of us learned, ever since grad school, that collaboration is the key to success in science? It is true that there is a lot of competition in science, but during recent years such competition has done more harm than good to science.
And I agree that there's sometimes a note of panic or even chauvinism in criticism of America's scientific position. At least one distinguished economist, Amar Bhidé of Columbia (who earlier this year gave a presentation at the center I'm visiting), believes Americans' real vocation is as "venturesome" consumers, whose zest for innovation benefits themselves and the world far more than "techno-nationalism" would.