Mike Molson Hart, who sells toys on Amazon.com Inc.’s marketplace, realized last month something was amiss. His company’s popular disc-shaped plastic building set, called Brain Flakes, had dropped precipitously in the ranks of Amazon’s best-selling toys as the critical gift-giving season approached.

Amazon goes into the holiday season with a newly magnified brick-and-mortar presence, giving it more opportunities to sell its Kindle e-readers, Fire tablets and other gadgets.

Will shoppers really spend more this holiday season than they did last year? It depends on whom you ask.

An awful lot of ink is spilled in the business press about the pressure brick-and-mortar retailers feel from Amazon and e-commerce in general, but not nearly as much attention is paid to the challenge they feel from the secondary market.

Brick-and-mortar retail chains, known for sprawling stores that stock a bit of everything, are trying to lift sagging sales using a different strategy: cozier spaces that sell very little of anything.

Every retail company has to cope with the changes mandated by operating in an omnichannel world, and seasonality confronts every one of them with pressures they don't see the rest of the year. But for companies in the retail hardware space, e-commerce and seasonal business peaks carry their own special challenges.