The link between education of workers and their wages is indeed probably less direct and/or strong than he makes it out to be. However, the increases in product

The link between education of workers and their wages is indeed probably less direct and/or strong than he makes it out to be. However, the increases in productivity you mention have to come from smart people thinking hard about how to do things more efficiently, so you could argue for more education from that standpoint. If you read the rest of the article in that light, he makes some interesting points. As for why higher productivity hasn't translated into higher wages, I think participation in the free market meant (and means) that gains in productivity are used to lower prices rather than increase workers' wages.