If it's the "risky undertaking" definition (Oxford dictionary). Then yes, it is gambling. By that definition, so is walking across the street, running a business, swimming in the ocean, driving a car, flying a plane or just life in itself is a "risky undertaking".
Out of all that they have to trust their own judgement on which items from a huge range will best attract our customers. When the new season starts we are dependant to a greater or lesser extent on consumer sentiment and the weather.
But we call that business - not gambling. Second thoughts, though....
