Seems dubious. I would expect doubling the amount of throughput would bring more shop revenue than doubling the waiting time of people in the airport. I can only buy so many slices of pizza.
They're not even cheaper than normal shops - more expensive than Amazon. What's the point?
This then makes you more likely to later buy an Armani t-shirt for $80.
The store in the airport is there to make you think the brand is glamorous, to convince you of its mystique, not to sell things.