Parent (and the article, although it fails to clearly draw the obvious link) could more accurately be said to be referring to a post-labor scarcity society.

In other words, a society where there is more labor available than we actually need to fulfill demand (caveat: in high-productivity industries).

To illustrate, take the article's example: the shift from an agricultural to industrial economy. Someone walks off a farm, they get employment in a factor. That factory worker can make 10-100 widgets / hr based on their labor.

Now look at the post-industrial economy we live in now. In software and heavily automated industries, the same single laborer can make 10-1,000,000 "copies" of their work product.

It seems fairly obvious there would be a breaking point at which productivity is so high that it disengages from driving demand. One worker can only buy so much, and his or her fellows can't buy anything because they're not employed.