From what I’ve heard, the very top professors in the U.S. today, the ones who are well known in their profession and often well known to the general public, make more (even adjusted for inflation) than they would have in the 1950’s. Back then even a really top professor might make at most the inflation-adjusted equivalent of $150,000. Today, the top professors, the ones who have, say, chairs at top universities, often make more like $250,000.
To put this in perspective, Einstein’s $780 per year in 1905 was about three times the salary for a laborer in a steel mill (according to Thomas Bell’s “Out of This Furnace”).
Bri2k
Also, in this day of full 2-car garages, cell phones, big screen TV and overseas vacations, it’s hard to relate to a simple urban life in 1905. The real question is, once the basics - living space, food, and occasional necessary expenses like clothes or shoes were accounted for, what was the disposable income? If he made 3 times a regular labourer, and had a relatively small family to support, presumably it was a pretty good life.
It should be noted that “chairs” often aren’t paid by the university. Often, what happens is some rich philanthropist will decide that he wants more work done in some area, and so will set up a fund to support some eminent individual working in that field. This is called an endowed chair, and the person who’s chosen for it is referred to as “the such-and-such chair of so-and-so”. For instance, Stephen Hawking (and Newton before him) is the Lucasian Chair of Mathematics at Cambridge.