Negative, jeff. There are at least two flaws in your theory.
1) these actually will still be built with free jw labor. The thermosteel construction and brick exterior is a decade old (at least) in dubbie lamd. They absolutly are not contracting anything out, except in places like ny city where union laws demand it.
2) kindomhalls are used quiet a bit during the week outside regular meeting nights. Meetings for field service are held twice a day in most halls as well as various elder meetings and the like. Then there is the issue of blasphemy mentioned by someone else.
It seems clear to me that this new design is all about flipping the buildings.