The prevailing narrative on the U.S. economy has downshifted, as three consecutive months of disappointing job growth raise concerns about a serious slowdown. There’s some good news to offset the bad, however: household incomes have finally shown a sharp gain, which means the typical family’s purchasing power is bouncing back. And the pace of car sales is accelerating toward record levels, with consumers more than willing to commit to costly long-term purchases. Meanwhile, several other indicators that don’t get as much attention as the monthly jobs report show sustained improvement in key parts of the economy. The monthly employment report...