I never caught that, although I did stay for the whole series in first run. Long time ago.
If DS9 stopped using the Ops set, it must have been for budgetary reasons. Sound stage floor space is a budget item, like rent, and maybe they moved DS9 to a smaller stage. This happened to both Lost in Space and Space: 1999.
In the case of Space: 1999, the Main Mission set took up so much space that they had to assemble it for all necessary scenes and then take it down to make room for other Alpha interiors to be stood up. The second season budget cut, IIRC, forced the production to move to a smaller stage elsewhere, and that's why the "Command Center" came about. And that was still a nice big set, just not as spectacular.
No, it wasn't anything like that, although I enjoyed your post. Ops remained fully available as a set.
The Defiant basically supplanted Ops heavily and the writers drastically cut back on having scenes set in the latter. (Note that I'm excluding Sisko's office, which continued to be used, although it too started seeing less time.) With the sorts of stories they decided to tell during the war arc, the Defiant was more suitable, and they just didn't have as much need to show Ops as the nerve center of the station. And Odo and Quark/Rom and Garak always got their scenes on the Promenade and had little reason to be in Ops. Neither did Nog or Ezri. I did an S6/S7 rewatch not long ago and was highly surprised at how little Ops was used. Since it was an amazingly cool set, it contributed to my overall disappointment. But as I said before, the "tough little ship" compensated.



I recalled the order and didn't think there had been a skipped week so early in the run, but didn't look it up to see if it was September 22 for "Where No Man." I appreciate you fixing my laziness.