I completely agree, it's a skill everyone should have. But it has no relation to any kind of proof that you've learned something, outside of communication courses. Despite this, it still impacts grades everywhere. That's a pretty definite disconnect.
Not that I think "standardized" tests are any better. Just that increased awareness of this kind of effect on perception might decrease its impact.
For reference, the story about the essay writer is here:
One of the university degrees I did (effectively an arts degree) involved doing a lot of essay writing as part of the major. While I don7t really use the field knowledge I studied in the degree I credit my reasonably ok writing ability to all essays I wrote - which I have put to good use in writing technical reports and user documentation that no one else wanted to write because it was seen as beneath them.
Even with the ability to catch copy-pasters with tools such as turn it in, there is always private essay/thesis writers you can hire (there was an article from one of these writers sometime last year).
I just have to trust that despite a fancy degree, the cheaters get caught out in the place where it really matters - the workplace.