I realize now that the reason those chapters flail so much is because I didn't have any sustained argument in them. They are collections of interesting and useful information on their respective subjects, they occasionally drift into brief arguments of a trivial sort, and collectively they provide the background material which will make the real argument in my last chapter possible. These article deadlines have given me a major incentive to work through all that material and find my arguments. It's all to the good.
I think I can have the current article in reasonable shape by this weekend. One way or another, I have to have it sent off by Wednesday, since I'm heading out of town then for a week and a half and won't be able to work on it; anyways, it's already technically overdue. When I come back, at the end of June, I hope to fend off the vortext of lassitude* and be productive despite the lack of these immediate deadlines which drive me to productivity.
* Credit to haggisthesecond for coining this phrase.