I share Brad DeLong’s fascination with anecdotes that illustrate historical comparisons of income. He posted one concerning the pay of a professor one hundred years ago.

our professor sees himself as a reasonable and badly underpaid man. He is not asking for what he would see as the “large salar[y], commensurate with what equal ability would bring in other lines of work ($10,000 to $50,000)”–or 20 to 100 times the then-current average level of GDP per worker, the equivalent today of between $1,100,000 and $5,500,000 a year. At 50 times average GDP per worker (roughly the mid-point of G.H.M.’s range, corresponding to a salary of $2.5 million a year), we are down to perhaps 4000 households in today’s United States (according to Piketty and Saez (2001)). That an “ordinary” professor could feel that his talents ought, in some sense, to earn such an enormous multiple of the average income is a sign of how unequal an economy and society the turn of the twentieth century U.S. was. Yet G.H.M.’s feeling of being sharply constrained by material necessity is real: as this professor goes through his budget, he expects the highly-literate and elite readers of the Atlantic Monthly to nod and agree (and we modern readers do indeed nod and agree) that his family is strapped for cash.

In the same vein, you might read my comparison of Frederick Douglass’ mansion in 1895 with the nearby neighborhood today.
For Discussion. The standard of living of average citizens today has soared past that of a rich person a hundred of years ago. Will this trend continue?