There's a mention in the book from the sibling post that he thought that single text slide is enough for the story background in shooters. Not necessarily truth looking at modern games.

Still, even then he was far from "let's use new library, just because it's fun to play with".

If you have even a passing interest in this, you will enjoy the book Masters of Doom, which is about the early days of id software. I think that's what the GP is referring to.