how can he be so good?

John Carmack, praised for his groundbreaking approach to coding, wrote every function from scratch for game engines like Doom. This approach reflected his deep understanding and control over the coding process, contrasting the modern trend of using libraries. While Carmack's methods may seem extreme, they underline the importance of skill, control, and efficiency in software development. Additionally, improving typing speed can significantly enhance a programmer's productivity and mental focus.