Thanks to everyone who commented on the post about technological unemployment.

From Onyomi:

Not saying I necessarily think this is what is going on, but one simple possible explanation for why technological unemployment could happen now when it never happened much in the past could be quite simply the greatly accelerated pace of change.

For most of history, technological change was very, very slow. The past few hundred years we've moved increasingly to a place where each new generation has to learn to function in a world different from the one their parents grew up in. We could now be moving to a world where each generation has to learn to function in multiple worlds over the course of a lifetimes, which may stretch the limits of human adaptability.