CHRISTOPHER BOOKER:

While some of America's most influential companies like Apple, Google, and Facebook project the image of a country on the move, Cowen views Silicon Valley as America's outlier. And data shows the notion that America remains the home of growth and change, is wrong.

One example of stagnation — the interstate migration rate declined 51 percent between the 1970s and 2013.

Another sign is job lock. In 1998, 44 percent of American workers had held the same job for five or more years. By 2014, 51 percent did.

And look at young entrepreneurs. The share of Americans under 30 who own a business has fallen by more than half since the 1980s.