It seems to me, the article believes PhD's are special: Why?
Because frankly, not everyone can do it. I started grad school with 21 other Americans. Of that group only 4 made it to the end. The wash out rate in graduate school is incredible. A Ph'D requires an original contribution to an active research area, which is something not everyone is capable of doing.
Because society benefits from scholorship.
However, not so much that we wish to PAY for "scholorship."
I think it was Edison that said he didn't wanna invent something that wouldn't sell, because if it didn't sell, it was worthless. Ditto PhD's: Unless scholorship PRODUCES SOMETHING, the who needs it?
Edison was short sighted there. I can think of a half dozen things in just Mathematics that even Mathematicians thought was pointless that turned out to be the central engine for some innovation in the real world. Poor Lobachevsky and Bolyai died in poverty, their research into Non-Euclidean Geometry was pretty much ignored, and yet Non-Euclidean geometry is pretty much the mathematical basis of Einstein's theories, which led to the bomb, which led to.....
Expand things out to the sciences in general, and you see tons of examples of stuff brushed off as useless or esoteric that turned out to be the most important thing in the world.
Of course, the reverse is true. Mathematicians wasted centuries on straight-edge and compass constructions and the best application of that now is a $0.99 app on the App store.
The fact is, you never know. Academic research is conducted at a bargain basement price for the world at large and typically forms the basis of innovations great and small. Some of that research will turn out to have practical applications, some won't.
This bullshit about it being "good for society" is the author's opinion: Society was just fine for centuries before the small blip in time between 1950-1970 when all the sudden, PhD's were fashionable.
They were fashionable long before that, just not here in the USA. Most of the growth in Mathematics and Science research was a direct result of Einstein and Von Neummann putting out the welcome mat at the Institute for Advanced Studies at MIT. The USA got a fire sale on European scientists and Mathematicians. Prior to that, American education kinda sucked.
Before the 1950's Europe was the center of research, and Ph'D's were pretty fashionable there. The trend of people coming to the USA for advanced degrees if fairly new. It used to be you went to Germany for Mathematics, England for Physics, etc.