Income is more concentrated today compared to the post-war period, but I don't think that makes the mean meaningless---it depends upon how much weight you put on a dollar held by different parts of the distribution. That being said, I think you'd be hard pressed to show that any part of the income distribution is worse-off in real terms than they were in 1950.
Incidentally, we only know about these changes in the income distribution because empirically oriented economists have been collecting and analyzing this data for many years.
I agree with you on the assumption that most likely all parts of the income distribution are better of today compared to the 50's -- on absolute terms. But _relative_ wealth becomes an important metric as soon as basic needs -- food, shelter etc. -- are satisfied.
Just to name a few. None of which is perfect, but at least better than the GDP when it comes to actually saying something about the quality and state of an economy.
> Rich man in a ghetto or rich man among friends. Pick one.
Rich people don't live in ghettos - that's why ghettos have a very "good" Gini coefficient. (Ghettos would be better off if they did have rich residents.)
I didn't hate rich folks when I lived in a ghetto. Was I doing something wrong?
