Ohh, a lot of spoken and unspoken things in the article made me think this was supposed to be a bug/quirk investigation. This makes much more sense.

It is a kind of bug/quirk: it implies that the compiler is not buildable from scratch in its current form. It depends on a binary that knows how to translate \n.

Right, I just mistook which thing was the bug/quirk.

The earliest reference on my shelf is Kernighan and Ritchie, 1978. Like you say, it's probably just been passed on from generation to generation. And it's easier to say "just like C" than to make up a new convention. Python uses the same convention.

The article is not about the convention, but about the mechanics of how the compiler came to 'learn' about the convention.