Amazon.com Inc. said on Wednesday it plans to close all 68 of its brick-and-mortar bookstores, pop-ups and shops carrying toys and home goods in the United States and United Kingdom, ending some of its longest-running retail experiments. The news marks a turning point for a company that began as an online bookseller and helped drive established rivals such as Borders to bankruptcy. Amazon said it would focus more on its grocery markets and a department store concept going forward. After opening its first book shop in Seattle in 2015, Amazon has tried out an array of ideas in retail: convenience stores without cashiers, supermarkets, and a format called “4-star” in which it sells toys, household items and other goods with high customer ratings. Amazon had aimed to reach shoppers in more places and bring its online touch into the real world. Its bookstores would pull from its vast data trove and showcase what people were reading, even the reviews they left on Amazon’s website. But the company’s innovations were not enough to counter the march toward online shopping that Amazon itself had set off. Its “physical stores” revenue — a mere 3 percent of Amazon’s $137 billion in sales last quarter, largely reflective of consumer spending at its Whole Foods subsidiary — has often failed to keep pace with growth in the retailer’s other businesses. Michael Pachter, an analyst at Wedbush Securities, said Internet-savvy Amazon was right to forgo the niche market of brick-and-mortar book shoppers, as bad a match as electric car maker Tesla Inc. opening gas stations. Pachter said Andy Jassy, Amazon’s new chief executive, likely made this call as he reviewed the retailer’s myriad businesses since taking the top job in July. “Retail is hard, and they’re discovering that,” he said. The company’s vice president of physical retail, Cameron Janes, departed Amazon after 14 years in November, he said in a LinkedIn post. Now chief commercial officer at retailer REI, he did not immediately return a request for comment. Amazon will close its 4-star, pop-up and bookstore locations on various dates and notify customers via signage. Workers will receive severance or can receive help finding jobs at any company stores nearby, such as more than a dozen Amazon Fresh grocery locations it has announced, the retailer said. Amazon declined to specify how many jobs would be cut.