Tech Will Rule These ’20s, Too

Does history rhyme? A century ago, the ’20s boomed, driven by consumer spending on homes, cars, radios and newfangled appliances like refrigerators, sewing machines and vacuum cleaners. Most Americans couldn’t afford the upfront cost of a lot of these goods, so manufacturers and retailers invented installment plans. Debt ruled as 75% of cars, furniture and washing machines were bought on credit.

The supply-side policies of Treasury Secretary Andrew Mellon, who pushed for tax cuts in 1921, 1924 and 1926, increased the capital…