you seem to implicitly assume that a college education is an unnecessary expense for most and that therefore, it shouldn't be really given away so readily. this suggests to me that you assume that the real purpose of college is job preparation. your reasoning makes sense from the perspective of a higher level institution (or corporation, or possibly a government) seeking to be as efficient as possible regardless of the impact on typical human individual's well-being.
college is not a 'factory' (or any sort of industry) that 'manufactures' workers for companies.