Why Is It So Hard for Clothing Resale Platforms to Make Money?

America’s overstuffed closets are crying out for relief. Their shelves are fecund; their rods, bowed. The situation under the country’s beds isn’t much better. If there’s one thing people in the US are rich in, it’s clothes that no longer fit, shoes that were never comfortable to begin with, and free hats and T-shirts they didn’t want or ask for.

Photographer: Logan Jackson for Bloomberg Businessweek

How to beat back this apparel overflow has long been an open question, both for people trying to free up some closet space and for those worried all that surplus will eventually end up in the trash. Most estimates ...