The Economist argues, as they would be expected to argue, given their free market leaning, that due to the glut of Ph.D.s and therefore the poor job market (in academia), it is a waste of time.   A Ph.D. who enters the job corporate world for anything except basic research has the wrong set of skills, according to corporate hiring managers, so it is actually better to hire a bachelor's or Masters degree and spend the time in the corporate world.  Numbers bear it out.  While a Ph.D. earns more than a bachelor's degree today the difference between a Ph.D. and a Masters is barely noticeable.

They have a point - until recently, any sort of college degree was for either the richest or smartest but once demographics showed that college-educated people make more, it became a political effort to give everyone a college education so they would make more money.

Except most people recognize it doesn't actually work that way - it simply means the best people will still get hired, regardless of degree, while some with a Ph.D. are mired in debt because the government did not say everyone should have the opportunity to get a college education for free, just the opportunity to get one, which meant student loans which had once been capped became unlimited.   Sensing unlimited money, college tuition spiked accordingly and the status quo was maintained; only the richest or smartest go to the best schools now.

Result; as I discussed in Why did 17 million of you go to college? there are 5 million janitors with Ph.D.s.   As The Economist notes, from the book “Higher Education? How Colleges Are Wasting Our Money and Failing Our Kids and What We Can Do About It”, America got over 100,000 new Ph.D.s between 2005 and 2009 but just 16,000 new professorships - part of that reason is because academia doesn't need more full-time jobs because they can get PhD students to do the teaching.  Talk about a Catch-22.

Does it seem to matter?  Not in science.   As the bar has risen, so has the need to accept a post-doctoral position, for less money than what a construction worker makes, to get considered for a lecturer position.    The glut of post-docs is so high that even if faculty jobs in something like the life sciences rose 5% per year, only 1 in 5 Ph.D.s would get one.   And academia is what a Ph.D. is primarily for; the research interests are too narrow otherwise.

Being a principal investigator is no easy task either; researchers from academia prefer the perception of autonomy under the grant system but it's highly competitive.

Clearly scientists are doing it for love, not money.  A site like Science 2.0 is proof of it.    However, there are limits to what ethical schools should be allowed to do.  Under the current system, schools will take everyone, knowing full well there are no jobs.   Then they will let them work as post-docs with the promise of better things in the future - though Ponzi scheme isn't the correct term it is certainly vaguely unethical to let students who want to do research underbid each other.   Unions came into play in the early part of the 20th century because corporation would let a glut of workers drive down prices.  Public and private universities now do the same thing.  Certainly unions mean higher wages, and with it fewer jobs, so the solution might be for schools to simply not lining their pockets and accepting far too many people.