Actually it's not just that averages are bad indicators -- the examples that he chose are obviously hand picked to make his case -- which to a knowledgeable reader destroys the credibility of the article in which he does most likely have a valid point.
For example he picks a mixed drink as a buying power indicator, but Norway has an off the charts "sin tax" on alcohol, which has little to do with the buying power for, say, a burger.
Perceptions of quality of life are always skewed by the attitude of the perceiver: you being on vacation, or the author being sick of Norway, for example.
I think the real thesis of the article is that there's a gap between Norway's perception of its own wealth and actual buying power, which really hit home for me when I interviewed for a job there (and ended up moving to Germany instead).
The more deeper seated cultural values, notably between how the wealth of a society is measured, are naturally harder to measure analytically. My theory (having grown up in the US and spent most of my adult life in Europe) is that the US is a society that is more "hero" driven -- and people that "make it" are more rewarded across the spectrum, whereas Europe tends to focus on a well-functioning welfare state. As a result, the American version of poverty is rare in most western european countries, but society is also less structured for empowering individuals. Both have their up and downsides.