So why then does the US military place people according to the ASVAB?
A college degree shows an ability to complete a specific course of discipline. It does not really even indicate aptitude in the discipline. Just the ability to follow through and complete the requirements. I suppose it shows a minimum level of aptitude in that you didn't give up hope and quit.
ASVAB doesn't indicate the ability to follow through with anything. It tries to hint at aptitude in a wide range of disciplines. It purports to provide your relative capabilities and interest in many topics.
That is why the military relies on ASVAB. They don't need to know your level of stick-to-it-ness or discipline. They will beat that into you or drum you out very quickly. They are more interested in where among hundreds of specialties you are most likely to fit.
I don't know what standards are like in the U.S., but at least where I went to university a good 30% (of those who were in the top 20% of the highly selective entrance exam) ended up getting kicked out because they didn't pass enough courses in their first or second year.
Yes, for some people it was an inability to concentrate, but I also know a few who put in more than the minimum hours but for some reason it just didn't 'click'.
I don't know if the US is suffering from grade inflation which lets through people who should have been failed, or if you are just in a bubble of people who are successful, but what you describe is nothing like what I experienced.
>The ASVAB measures cognitive ability like other common IQ test, but it dependent upon the individual’s previous education for successful scores. It removes the individual attention received in common IQ test, but gathers much of the same information.