David Streitfeld's Times writeup on Amazon's latest customer-service push is generally informative, but he buries the lede. Here's his explanation as to why the retailer is putting up new warehouses all over the country: This multibillion-dollar building frenzy comes as Amazon is about to lose perhaps its biggest competitive edge — that the vast majority of its customers do not pay sales tax. After negotiations with lawmakers, the company is beginning to collect taxes in California, Texas, Pennsylvania and other states. But Amazon hopes that the warehouses will allow it to provide better service, giving it the ability to up-end the retailing industry in an entirely new way. So they needed a new way to have an edge, and they happened to go with more warehouses?