Is there any reason to think they would graduate with useful knowledge otherwise? The kids in my day who did poor may have graduated - but they still lacked kno

Is there any reason to think they would graduate with useful knowledge otherwise? The kids in my day who did poor may have graduated - but they still lacked knowlege and to the diploma was paper... also those kids who don't pass will hold those who do pass - as the next year teachers waste time teaching what the majority already knows