the important word in the first sentence is "expatriates". It's a pretty narrow category of population, with, let's say, consumption patterns and "requirements" which may not be replicable for the whole population.

The price index does not include the price of spaghettis at the nearby grocery store, but includes that of the home-delivered gourmet lunch for 12 with waiter (I'm making this up, but it's probably close to reality) as well as the cost of private schools and the like.

In the long run, we're all dead. John Maynard Keynes