Technological progress should cause increasing economic inequality, because the bottom end of the scale is firmly anchored at zero (someone taking a vacation), while technology gives the top end ever more powerful levers. So the interesting question is not why economic inequality is increasing, but why for a few decades in the mid twentieth century the trend was reversed. There are probably several factors at work he…
Many of the arguments about economic inequality in this thread seem to be predicated on the notion that we are talking about comparing salaries or car brands. Don't be jealous of your neighbor for having a higher salary or a better car, and why should he have to give up more of his money via taxes just to enhance your lifestyle... seems to be the gist.
But income inequality is rooted in the question not of does your neighbor have more goodies, but how do we divide the spoils of our shared enterprise. If you and your neighbor are partners in the same firm, and you are working your ass off so that he can ride around in a Benz, things are a little different.
It is interesting to observe that when this argument is couched in terms immediately relevant to most of the posters here, the response on HN is quite different. I.e. "I have a great business idea, I just need someone to code it for 1% of the business equity". There are markedly fewer posters defending this notion, or condemning the hacker who wants a bigger share as exhibiting some kind of perverse socialist urge toward income redistribution, than there are posters in this thread defending the same notion expanded to society as a whole.