Are the top two pair of shoes sold out? Who knows? Who cares?
What we know is that this is a marketing tactic designed to get you to buy either of the bottom two pair of shoes, right?
What happens after the customer purchases one of the pair of shoes? Well, World Soccer Shop generates profit. Nike generates profit. The email marketing team gets closer to earning a bonus. The merchandising team gets one step closer to earning a bonus. The analytics team measures the future value of the customer. Vendors attribute the order independent of bonus structure.
But what happens to the customer? What does the customer purchase next?
Few people know the answer to that question, and for good reason. Almost nobody measures the big 'ole bubbling ecosystem known as our "brand".
In project after project, the act of causing a customer to buy a specific item changes the trajectory of the customer ... usually for good ... sometimes the outcome isn't so good ... but almost always, the impact is not measured.
Measure the impact. Contact me (firstname.lastname@example.org) if you cannot do the work yourself. It's important work, no doubt about it.