With a history degree, you are required to analyze a complicated situation with a large number of factors and come up with your own assessment, then articulate it with support.
Mechanical engineering gives you templates to solve various problems that are specific to the manufacturing industry, and so much so that these can't be applied to other problems.
I think you are mischaracterizing what's involved in getting a degree...
Universities tend to require at least SOME diversity in their education, so even someone majoring in sciences will probably have at least some exposure to non-science courses. (The university I went to for computer science also required me to take 2 biology, 2 physics, 2 chemistry, and multiple social science courses, which in my case involved history, economics, and english.)
Secondly, even in courses that do focus on science, they often involve more than just "how to I solve this problem?" Students have to learn to communicate (through lab reports/presentations of their work), i.e. the type of thing you said history prepares you for.
Lastly, even when dealing with the technical aspects of science/engineering degrees... they are more than just narrowly focused "how do I fix this problem?" You still have to know how to analyze situations, perform risk assessments, etc. Things that are applicable outside of science courses. Any math courses you take will help in understanding things like economics. Any chemistry courses you take will help you understand issues with the environment and/or biology.
So much of what people are talking about, in this topic, is actually JOB TRAINING which you get from community college or a trade school. IN both of the cases above, the person would have to get additional training. But the history degree, if mastered, would provide better education for a career.
Actually, a more accurate claim is that a history COULD provide a better education for a career.
But, you have to figure... what type of career are you talking about? There are very few history-specific jobs out there. So where else could you work? Anything having to do with manufacturing (e.g. car companies, resource extraction, etc.) MIGHT like your ability to analyze/communicate, but they will also like the science/engineering guy's ability to better understand the technical side of things. Financial services companies (e.g. banks) might prefer someone with a business or economics degree.
The fact that many social science majors get jobs outside their field of study may have less to do with "My degree helped teach me skills that helped me in my new job" and more to do with "The employer just wanted SOME degree, and this is what I had".