Why would Amazon give up its precious tax advantage? This week, as part of an excellent investigative series on the firm, the Financial Times’ Barney Jopson reports that Amazon’s tax capitulation is part of a major shift in the company’s operations. Amazon’s grand strategy has been to set up distribution centers in faraway, low-cost states and then ship stuff to people in more populous, high-cost states. When I order stuff from Amazon, for instance, it gets shipped to California from one of the company’s massive warehouses in Kentucky or Nevada.

But now Amazon has a new game. Now that it has agreed to collect sales taxes, the company can legally set up warehouses right inside some of the largest metropolitan areas in the nation. Why would it want to do that? Because Amazon’s new goal is to get stuff to you immediately—as soon as a few hours after you hit Buy. …

It’s hard to overstate how thoroughly this move will shake up the retail industry. Same-day delivery has long been the holy grail of Internet retailers, something that dozens of startups have tried and failed to accomplish. (Remember Kozmo.com?) But Amazon is investing billions to make next-day delivery standard, and same-day delivery an option for lots of customers. If it can pull that off, the company will permanently alter how we shop. To put it more bluntly: Physical retailers will be hosed.