>Consider that not all communication is about "getting ahead".

But you don't need to follow any advice if you do not seek to get ahead (i.e., better) in some sense. So, that doesn't make sense as a counterargument. OP's point is that you can become better at explaining, but that on its own does not add value. This is quite evident in scientific writing. Plenty of well-written papers are rejected if they do not provide sufficient value.

You’re implying that the only possible goal is to “get ahead”, which is not true. There are clearly other goals one can have in writing and in life.

No, I'm not implying that. I'm saying that you do not need to heed to advice if you do not wish to become better, for whatever definition of better or 'getting ahead' you use. Saying that you don't want to get ahead is like a null statement. It doesn't add anything and is quite irrelevant to this discussion. It's like saying, "but I don't care; I'll do my own thing". You can say that for anything.