Home Depot turned the building-supply warehouse into a DIY superstore in 1979

American home improvement in the 1970s ran on corner hardware stores and small regional chains — limited stock, markup pricing, and advice of uneven quality. Bernie Marcus, CEO of the Handy Dan improvement-center chain, and its finance chief Arthur Blank had spent years thinking about what a better format would look like. In April 1978 a corporate power struggle got both of them fired from Handy Dan.

Unemployed and near 50, Marcus built the company around the idea he later described as a one-stop shop for do-it-yourselfers. Investment banker Ken Langone assembled the investors, merchandising expert Pat Farrah joined, and the plan was explicit: a chain bigger than traditional hardware stores, with better-trained staff — stores where plumbers and electricians who had done the work would show a homeowner how to do it too.

The first two stores opened on June 22, 1979, in leased spaces in metro Atlanta that had been JCPenney's Treasure Island hypermarkets — big boxes on the highway, ready-made for the format. Marcus and Blank stacked merchandise high, sold at deep discounts, and let shoppers serve themselves out of a building sized like a wholesaler's warehouse rather than a shop.

The format compounded fast: public on NASDAQ in 1981, 19 stores and over $256 million in sales by 1984, and by 1989 The Home Depot passed Lowe's to become the largest home-improvement retailer in the United States. It is now a 2,300-plus-store business worth close to $400 billion — the largest thing on its scale in the category by far.

Open the warehouse to the public, staffed by tradespeople

The baby-boom housing stock and a generation of new homeowners created millions of DIY customers that small hardware stores could neither stock nor teach.

Selling at warehouse scale undercut every corner store on price, so the discount funded itself in volume rather than in margin.

Trade-trained staff made the big box trustworthy: the free advice was the product feature that converted a trip to the contractor into a trip to the aisle.

The founders' firing removed the incentive to defend the old format — they had nothing to cannibalize and everything to prove.

A warehouse is a format, not just a cost: open it to people who were never meant to shop there, staff it with people who know the work, and the discount becomes a school that grows its own customers.

The Home Depot's warehouse superstore became the template for home-improvement retail worldwide and forced Lowe's and others to copy the format to survive. The company kept the model through the e-commerce era by wiring stores as fulfillment nodes. Marcus and Blank, fired from one hardware chain, ended up building one of American retail's most valuable companies on the format their old employer never adopted.