First, the big picture. Here is the entire market for Ph.D.'s, including those graduating from humanities, science, education, and other programs. The blue line tracks students who have a job waiting for them after graduation. The green line tracks those signed up for a post-doctorate study program. The red line stands for the jobless (though a sliver of them are heading to another academic program).
The pattern reaching back to 2001 is clear -- fewer jobs, more unemployment, and more post-doc work -- especially in the sciences. A post doc essentially translates into toiling as a low-paid lab hand (emphasis on low-paid). Once it was just a one or two year rite of passage where budding scientists honed their research skills. Now it can stretch on for half a decade .
The described situation—PhDs not getting jobs—is kind of sad for those pursuing higher education. Once upon a time, only some soft areas like humanities and arts graduates had difficulties finding jobs but now it looks like science and engineering is facing the same problem.