"Although hardly anyone noticed the change at the time, it is difficult to imagine a more dramatic contrast than the decades just before 1970, and the decades since then. Those were the years in which science underwent an irreversible transformation into an entirely new regime."
This is consistent with what the economist Tyler Cowen argued in his book "The Great Stagnation: How America Ate All The Low-Hanging Fruit of Modern History, Got Sick, and Will (Eventually) Feel Better."
 Race Against The Machine: How the Digital Revolution is Accelerating Innovation, Driving Productivity, and Irreversibly Transforming Employment and the Economy
In "Race Against the Machine", economists Erik Brynjolfsson and Andrew McAfee ask the question: Could technology be destroying jobs? They then expand on that to explore whether advancing information technology might be an important contributor to the current unemployment disaster. The authors argue very convincingly that the answer to both questions is YES.
 The Great Stagnation: How America Ate All The Low-Hanging Fruit of Modern History, Got Sick, and Will (Eventually) Feel Better.
Cowen's central idea is that the pace of innovation has slowed, and that we are now on a "technological plateau" that makes further growth challenging. If you consider technology in the broad sense (energy, transportation, home, etc), this makes sense as things have not changed a lot in recent decades. However, I think it is also true that progress has been highly concentrated in information technology and communications, and that things continue to advance rapidly in this area. Cowen notes this but seems to feel that the Internet is the only really major innovation.
We've picked all the low hanging fruit - in technology and resources.
Our cars haven't really change much in 100 years. Same basic engine, just added computers (we did that in the _1970'_).
We're only incrementally improving technology (cars with navigation).
Our current innovations (Twitter, FB, Google) don't produce many jobs and in fact reduce number of jobs. People will spend the night on FB vs going out to dinner, a movie, etc. You don't need to go out to cure boredom/socialize.
Also, Social websites don't produce much commercial activity (compared to say the automakers building Detroit into a first tier city in the last century).
We're patenting one click check outs, but we haven't found a good (economical at scale) replacement for the major components of our economy - e.g. the internal combustion engine and fossil fuels.
The US has has an abundance of cheap land an resources PLUS the country was lucky enough to grow up in the industrial revolution when technical innovation was relatively easy and world changing (compared to now where it's much more incremental).
We're going to stagnate until someone (US,Chinese,Indian,other) makes some big leaps in alternative energy and other advanced technology.
Web apps aren't going fix our economic problems (however useful they are).
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