The apparel industry has a big problem. At a time when the economy is growing, unemployment is low, wages are rebounding and consumers are eager to buy, Americans are spending less and less on clothing.

The woes of retailers are often blamed on Amazon.com Inc. and its vise grip on e-commerce shoppers. Consumers glued to their phones would rather browse online instead of venturing out to their local malls, and that’s crushed sales and hastened the bankruptcies of brick-and-mortar stalwarts from American Apparel to Wet Seal.

But that’s not the whole story. The apparel industry seems to have no solution to the dwindling dollars Americans devote to their closets.

Many upstarts promising to revolutionize the industry drift away with barely a whimper. Who needs fashion these days when you can express yourself through…