I read Stereophile and TAS and I've also noticed a decline in writing quality. I have attributed this to a lack of editing. I think that the editors now just check for factural accuracy and let the articles go through with poor wording.
Let's face it; it's hard to make a review about a DAC interesting. What can you say that hasn't been said before? I suspect some of what we are seeing is the result of the reviewers trying harder and harder to say something original.
I never thought about A.I. being a potential cause of this but I think that A.I. wouldn't be particularly good for writing audio equipment reviews. Maybe I just don't understand the capabilities of A.I. but the weird phrasing and odd syntax we are seeing is probably a clue that A.I. isn't being used. A.I. is better than that.