The work of a steveadore, one of the examples given, has been vastly automated and unionized. The work is much physically easier than before: operating a crane vs. manually moving cargo. Dockworker's unions have negotiated strong agreements related to overtime pay which guarantee time and a half. There are a far smaller number of employees needed, and those employees want to pack in as many hours as they legally can, to reap the overtime benefits. Automation of an industry can actually lead to longer hours for the fewer employees still working in the industry.
Since there are far fewer well paying positions like being a longshoreman, people who may have once gotten a job on the docks have to compete with everyone else for service jobs. The service jobs don't pay enough, so many need 2 or even 3 jobs to keep their families afloat. The need for multiple jobs explains why this class of people is working longer.
I agree. I'm 13 and spend over 120 hours per week in the oil mines of North Dakota. I puked when I read the first comment and slammed my laptop shut because I was shaking with disgust.
Cal Newport's advice is more along the lines of "Do what you're really good at, rather than only what you love."
That's interesting, as other career gurus argue the opposite view. For example Barbara Sher, author of "I Could Do Anything If I Only Knew What It Was" gives the example of herself as an unhappy stay-at-home mom. She is an expert at cooking, changing diapers, and other aspects of child rearing. If she pursued what she was really good at, she'd be limiting her options to work as a nanny, or perhaps open a day-care center.
As a writer, Rand gets better as she gets shorter. I'd say she never gets to the point where she could be called a good writer, but she does sometimes reach for and achieve passable.