Walmart is still the largest retailer in the U.S.—
. Although Amazon is expected to be responsible for about 15% of the total retail market by 2026, the company is consistently losing customers in one area of its business all while rapidly expanding in another.of the online grocery shopping landscape, Coresight Research says that the last three years have seen a decline in online grocery shopping at Amazon. In 2018—12 years after it started selling groceries online and one year after purchasing Whole Foods—70.