Grocers have held back for good reasons. Like many bricks-and-mortar merchants they fret that online commerce will shrivel sales in stores but not the costs associated with them. Grocery, with its tiny profit margins, adds complications. Virtual shopping-carts contain dozens of low-value items, which must be stored at different temperatures. Retailers can either get in-store staff to pick them off the shelves, which becomes disruptive as volumes rise, or build dedicated warehouses, which is costly. So are home deliveries: even in thickly settled Britain each one costs grocers around £10 ($16), but shoppers typically pay little more than £3.
