Back when I was at university I met lots of people working towards CS or engineering degrees either solely or primarily because that's where the jobs where. They had no real passion or interest in the field beyond that. Some of them had even made a conscious choice to not study what they where really passionate about because the they knew the job market was bad in those fields.
Also most people I know who majored in so called un-marketable fields did so knowing full well what the job market looked like and did take that into account. They just came to the conclusion that studying what they wanted to study, rather than what was economically expedient, was more important to them. A few of them have even, through hard work and dedication, beaten the odds and managed to end up in a well paid dream job in their chosen field.
Also most people I know who majored in so called un-marketable fields did so knowing full well what the job market looked like and did take that into account. They just came to the conclusion that studying what they wanted to study, rather than what was economically expedient, was more important to them. A few of them have even, through hard work and dedication, beaten the odds and managed to end up in a well paid dream job in their chosen field.