The figures are correct. If your figures are right, I would assume that the wealth here is controlled by a small group.
How do people live here? First of all, people pool their resources. The family unit, if only out of necessity, is stronger here. Children live at home until they are married and sometimes stay at home after marriage. Most people do not own cars. People do not enjoy the lifestyle of the expats who read this website. They seldom, if ever, dine out. If they can not afaford health insurance, they use substandard public hospitals. A large percentage (this grew dramatically after devaluation) live below the poverty line. In the northern provinces there is growing malnutrition. In a nutshell, local expectations are very low compared with those of Europeans/Americans.
Why do Europesns/Americans stay here? Most are in a transition. Just passing through. They often like to rant and rave about how bad the US is, stating or implying that Argentina is somehow superior. The fact is that few would be willing to settle down here and live like a local. There are some people who have married locals and for personal reasons are stuck here.