All that said, governments haven’t done enough to help the situation — and have done a lot to exacerbate it. Closest to home, of course, is gridlock in Washington. Anti-deficit fervor has led to a meat-ax approach to spending cuts, under which nondefense discretionary outlays (which include key pro-growth areas like research and development and infrastructure) have fallen in real terms by nearly 20 percent over the past five years, at a time when they should be growing substantially.

Meanwhile, Congress has not passed a comprehensive tax reform package in three decades, which has given clever experts room to develop loophole after loophole, particularly for multinational companies eager to cut their tax bills by sequestering profits overseas.

Fueling still more fear among consumers and businessmen alike is the looming presidential election and the surprising strength of contenders like Donald J. Trump and Bernie Sanders, who promise unconventional, and potentially disruptive, changes if elected.

Europe is in far worse shape. Bedeviled by a poorly constructed single currency system, the Continent has lurched from crisis to crisis as weaker countries like Greece fail to keep up with the German juggernaut.