The purpose of the educational system was originally to educate the future voters, that they could be an informed and discerning electorate.
Think about it: What vocational education does a worker need to be farm laborer? Which was the primary occupation in America, until after the civil war. Most skilled trades were trained through apprenticeships.
And in most states the remnants of that are reflected by the requirement that you complete 8th grade before you can drop out of school.
That was the purpose of primary education. The 3 Rs. Secondary education was always intended to be vocational.
Ag was Vocational Agriculture, that taught wood working, mechanical skills, crop selection, water and erosion systems, etc. That morphed into shop classes, but many high school students were certified welders, or ready to enter plumbing or electrical apprenticeships.
Home Economics was intended to teach cooking, nutrition, housekeeping, child care, budgeting, and other domestic skills. That may seem trivial, but we have a generation that does not know how to cook. I saw an interview in 2008 with a woman leaving a food bank who said, "Thank god there are no dried beans. I must have 50 lbs. of dried beans at home and don't know what to do with them."
The business department at my high school was well known. I learned typing and business law, basically contracts and torts. Kids who concentrated in that area learned double entry bookkeeping, payroll, tax planning, and probably a bunch of stuff I didn't know about.
Physical Education was designed to get the couch potatoes moving once a day, but also to prep young men for military service. If you got an A in PE you could sail through basic training. That went hand in glove with social studies. You could not graduate without passing a year of Civics.
College prep courses were not directly vocational, but I graduated with a year of college level physics, chemistry, trigonometry, calculus, the logical discipline of Euclidean geometry, two years of a foreign language, and the ability to write lab reports, technical papers, and short stories.
Grade inflation had not become a thing, The average GPA was 2.5 and a perfect 4.0 was achieved by perhaps one in 50. A perfect score on the SATs was unheard of. The reason businesses require a degree is that high school has become little more than advanced child care.
