If the scientific weltenschauung is correct: Should we not attain mastery of current knowledge by highschool?

If science is correct then our own mind will be explained by it. Why do we wait until college to pursue in depth studie? And why are we then only specialized in one or two branches? Is it not a waist of time with music cl, art, reading stories, physical education, etc...? And why are not clear cut simple explanation used to teach how everything works? We need this clear cut approach to build cars, microwaves, refridgerators, computers, to perform surgery, etc.