What you have presented here @kingpins is "mean" income, which is as you correctly point out via example quite useless for assessing the result to the average person being measured. The graph @madamswer presented however was of the "median" wealth by country, which is a highly valid way to compare across countries, because if lining up citizens from wealthiest to poorest and selecting the middle citizen doesn't give a good idea of how well wealth is spread in a country, then I can't think what better way you might propose.
Perhaps picking the mark 1 standard deviation either side of the mean might give some additional useful information, but the median is the best snapshot I would have thought - Eternalgrowth
