Oral transmission of complex culture is one of the things that separates us from "the state of nature". As we lose it, we move further away from the beasts that conquered the planet and closer to the squirrel.

Transmission of complex culture is what separates us (and enables this complex culture in the first place); oral medium is merely one way to do it. Being the first one, it's probably not the best.

Considering it's the only medium that needs literally nothing but ourselves to work, I disagree with your statement. But to each its own.