I wonder how much the Shopping Arcades have developed to off set the price controls put in place when the airports were privatised? As you may recall, there was a strong limit on how much the landing fees could go up each year. It was no surprise when LHR changed their landign charges policy from 'seating per aircraft' to 'aircraft' so as to increase their income and squeeze out the regionals. (Still an ongoing problem 25+ years later!) Then they started upping the prices of the shop lets and redesigning to incorporate more shops and everyone else followed. The Conservatives wanted to privatise but knew that rising landing fees would be blamed on them. So they put controls in price which were then side stepped. No one could have predicted that ...
Parking was then incorporated as another high income stream. They learnt this one from British Rail who had already hiked parking prices to the point where their car parks started to empty and surrounding streets started to fill up with commuters parking in surburban side streets. Consequently to that the local Councils had to introduce parking restrictions so that locals could park in front of their own houses - had this happen to us.
I might be throwing hand grenades too freely, I sit to be corrected.