shoitim

its very possible that most people don’t have the capabilities to learn everything .there’s a concept of niskatnu hadoros. also many gedolim hold its better to do more iyun then to have for bekiyus, also realize the yeshiva system spend years just trying to get all the shtus out of kids heads (sports, sometimes movies and other bad influences of this world). which takes time and practically makes it that they won’t leave yeshiva knowing what they used to in the old days
I myself learned with someone who knew all of nashim nezikin cold when he was 18 ,but he was a Talmud of r Baruch ber in Europe and he knew shas cold but he never pushed the Derech unto his talmidim