Airports are divided into two zones - landside and airside - with a security boundary between.
I have generally found that the sandwiches and drinks are cheaper on the landside. (One major UK retailer sells good sandwiches in its landside shops, but not in its airside shops). And in some airports the best coffee is landside.
Makes sense. Once the passengers have gone through security, they are captive. The airport can get an economic "rent" by making them pay more for food and drink while they're waiting for a flight. (Isn't that the real reason they want us to check in so early.)
I hate being ripped off. So I try to buy anything I need on the landside, before going through security. And at some airports, that includes coffee.
Oh, but you can't do that anymore. For security reasons, you now can't take coffee through from landside to airside. Yeah, what do you think I've got concealed in my latte - nail scissors?
Any stupid regulation can be justified by appealing to security. But it doesn't take much to work out who really benefits commercially from these so-called regulations.
See previous post No Fly on Us