It makes people spend money! Many a time I have seen passengers walking in front of me who have had their attention caught by a special offer, one-off promotion and the like and diverted towards the cash till! It's the same scenario with those awful games machines. They too bring in loads of revenue for the airport because people use them very frequently. The airport is quite obviously manipulating passengers but if people are stupid enough to fall for it, then it will continue. The narrow and poorly signed route to the gate will become much wider and better signposted once the airside refit is complete. But yes, you will still have to walk through it I'm afraid.
I think a lot of posters are not reflective of the real world, where people could not care less about the views of the aircraft. I know they hate to be bored and moan if there are no shops or eating facilities. This is one of my pet hates in T3. If the flight is delayed and you are airside there is nowhere decent to get food, etc. I would rather have the facilities and not use them most of the time than not have them and be stuck.
Also these retail outlets pump up revenues so the cheap flights we have come to expect may continue into the future. Raising revenue from sources other than airlines allows the airport to charge the airlines less, which makes routes more attractive, yet they can continue to invest in infrastructure required. This is turn means more aircraft, from more carriers for the likes of us to spot.
Someone has to pay for the running of the airport. The airlines have made it quite clear that their customers are not willing to pay over the odds for their tickets. What the airports have discovered is that customers are willing to spend once they are IN the airport.
Its not rocket science!