Why were lamplighters better off in the long run, is "lamplighter" a term that means more than just somebody who goes around lighting the streetlamps at night? Honestly that seems like a pretty decent job even today, if we still needed it to be done.
The subtext of observations like those are that wealthy aristocrats in the age of full lamplighter employment would be better off materially working as a Walmart checkers today, and there's some truth to that, but the implication that Walmart checkers today will be better off when computers eat their jobs does not follow inexorably from history (the idea that it does is "Whig history"; the past sucked except in serving its role as the stepstones to our glorious future; take that, and the famous WW2 bomber survivorship bias graphic, and you have the problem with the logic of that last paragraph).
