I wonder how much revenue those "duty free" shops really make? I never ever buy anything there as it's a pain to carry stuff with you all the rest of your trip and prices and product selection are totally unattractive to me. It's fun at remote vacation spots to see how well very basic plain vanilla functional airports without all the shopping and mall fanfare do work with only short distances to walk and easy processes.
Many real world malls are dying these days maybe airport malls will too?
What everybody seems to need is a cafe maybe a restaurant and something like a bookshop and early announced departure gates not last minute only.

Less Hair
I agree re book shops as I spend too much time looking at screens though it does mean a bulky shoulder bag on long trips, but it does get lighter as I drop them off in hotels on route for cleaners etc. Good ones I do bring back though I know I dropped some early JK Rowling stuff at my nieces recommendation in SIN which seeing the prices for first additions was one of my larger financial mistakes 🥲 As for the shops I will pick up stuff for myself if price is right or difficult to obtain in UK, but always on way home. However in the past I have taken Cuban cigars into the US for colleagues 😉

Cheers
Mr Mac