Exactly. All of the points made about free or semi-free education can just as easily be applied to the 'harder' subjects, and while there are plenty of examples of well-versed, successful, self-trained members of all disciplines, they are generally the exception and not the rule.

Not quite as easily. First, learning those subjects often requires access to specialized equipment and facilities. Second, depending on your threshold for "successful," a liberal arts degree may not be much more helpful than self-study. The typical result of a liberal arts degree seems to be that the student has spent a lot of time learning about the field in question but still has little chance of being employed in that area. By comparison, a degree in engineering brings a huge improvement in employability as an engineer.