But GDP per capita is a pointless measure if you don't correct for the cost of living. The more interesting number is when you correct for how much you can actually do with the money earned. That's PPP (purchasing-power-parity), the measure in the article.
Note that that doesn't measure quality of life. Qatar may take the top spot in that ranking, but has large amounts of foreign workers employed under some not-so-nice conditions. Almost 90% of the population are foreign workers with temporary residence status: https://en.wikipedia.org/wiki/Demographics_of_Qatar