Dorothy Sayers (a contemporary of CS Lewis and JRR Tolkien, and friend to both) wrote an essay about this about 60 years ago, titled "The Lost Tools of Learning" https://gbt.org/text/sayers.html
I attended private Catholic schools in NYC starting in 1960. I remember being told early and often by the nuns, brothers and priests who taught that "you are going to live 80 years, we will be teaching you for a small fraction of that time and it's impossible for us to teach you everything you are going to need to know. What we can teach you is how to learn on your own." And they did.