Is there a reason to believe he’s stopped? The articles are clearly very labor/time-intensive, so the current lag isn’t all that unusual.

Well, Bartosz used to publish 1–5 articles per year, but hasn't published any this or last year. I assume he's just got other things to do in his life, which is absolutely fair and I'm grateful for every one of the articles we got gifted and all—but at the very least he is taking a pause right now.