Maybe I'm just in a good mood this sunny Friday morning, but I find this  to be one of Will's better columns.  Even somewhat non partisan.
I get what he's saying, that while technology can greatly increase the productivity  of a mill, for example, allowing for increases in both wages and profits, this is impossible with labor-intensive occupations such as musician or medical care.   Thus, these labor intensive jobs will have to be subsidized in order to compete, which generally brings in the government whether Republican or Democrat.  
Looking way  back on my old  summer job of pulling lumber on the  greenchain  I can see where it's been largely automated, but thinking of my face to face contacts with students in school or the mentally ill in a clinic I find it hard to imagine how even artificial intelligence will replace the quality of the human touch.  So  how do we fund these socially useful but labor intensive professions?