Amazon is indeed gaining market share. Currently, Staples NAD is losing nearly 10% market share year-over-year, while retail is down nearly 40%. Reasons include, but not limited to, products and services costing more in retail and the B2B space, and Amazon's ease of ordering. In the B2B space, Staples typically takes a loss on the sales of office supplies, which is why they're focusing on other, high margin BOSS categories, such as tech, furniture, and print.
Account consultants have already been briefed on Amazon Business Prime, which is expected to cause a disruption in the B2B space. This is why Staples is focusing on NAD, or North American Delivery, because it's believed that this space is the only business unit that can survive the "Amazon effect." This isn't even including Walmart, who is making plans to compete with Amazon in the B2B space. Their plans include duplicating Amazon's success, while positioning their retail space to an advantage. This will all be at the cost of other major retailers.
Like it or not, consumers and businesses want a high quality product and service at a low cost, and don't want to physically travel to acquire their goods. No matter how good or bad the economy was, is, and will be doing, buying habits have changed in favor of Amazon.