The 12.4% of people who couldn't get a job because they went into chemistry is ultimately their fault, they didn't spend enough time looking at the market and filling a need. If there is an over-saturation in the market then that will naturally lead to high unemployment. It's not the economy's fault, because the economy doesn't choose anything. It's simply a state of what is needed and what is not needed. If someone decides to go into something that is not needed, then that is their fault, for either ignorance of the job market or acceptance of an over-saturated market.
Work ethic is very important, as it often compensates for bad choices. But a combination of a work ethic and good choices is almost a guarantee of success. And luckily, both of those are mostly controllable as an individual.
I have worked as a software developer/engineer/architect for 5 years now. I constantly stay on top of the newest technologies, because if I was still stuck using Fortran in today's market it would be next to impossible to get a job. And it wouldn't be the markets fault for not having enough Fortran jobs out there, it would be my fault for lagging behind and making poor choices, despite however amazing my work ethic might have been.