Very insightful article. The term "quality of life" is albeit elusive because it's fundamentally subjective. Material wealth and abundance can, without a doubt, contribute to a higher quality of life, and the absence of that material goodness can indeed lower the quality of life. Nevertheless, material wealth and technological advancement do not equate to the quality of life. As one musician said, "Better is the enemy of good."
There is a diminishing return on what material height adds to quality of experience. I remember hearing something in the US that it is around a salary of 70 - 100k a year. Enough to enjoy, not enough to have to worry about the money itself. It was a while ago though so don't quote it :D
Makes perfect sense to me :)