I'm cynical. I suspect the airports make good profits out of these ventures or they wouldn't devote so much space to duty-free shops or route passengers through the terminals in such a way that they have to walk through these areas. Last time I flew home from Bangalore, the new airport terminal had people on duty selling alcohol and designer purses at 5 AM. There are some genuine good deals to be had in alcohol and tobacco because those items are so heavily taxed. I suspect that people then pick up other items on which there's little or no savings because they're in the store anyway, or they need last-minute gifts or they want to spend down their supply of local currency. Or they're bored because they got to the airport 3 hours ahead of time and sitting in crowded, noisy gate areas is unpleasant. (And there's a theory that gate areas are designed to be crowded and noisy with uncomfortable seats so that people will drift into the stores and restaurants.) I have to admit I've bought local wine in DF with no idea what it costs on the outside and that's probably how a lot of people shop.

My tactic is to swoop by the alcohol section, pick up a bargain in scotch or gin based on what I know of the prices and generally ignore the rest. We don't know anyone who smokes, so we never look at the tobacco. Then I head for whatever lounge I can get into.