Atrios explains it quite well here. A sample:
“My problem with economists is that even many of the smart ones tend to instinctively equate the social welfare of a country with its per capita GDP. This is absurd, and it isn’t as if they don’t actually know this, but nonetheless it tends to be how people operate.”
Of course there are a whole bunch of rich and powerful people in any country who are quite pleased to see that this is adopted as orthodoxy. So long as the overall economy grows, they can damn anyone who points out that the share of the wealthiest one percent may be growing faster than the total GDP (i.e.: everyone else’s share is shrinking). That those in the media elite from the owners to the top-tier anchors to the commentators-at-large are almost all in the top bracket only serves to reinforce the big GDP = good mentality.