Not sure I agree with this (I agree there is no fixed/procedural timetable, I am referring to the political timetable)If this doesn't pass by mid-December it is dead. Reconcilliation takes time. It's not just the passage. There are required procedures which have a specified timetable for doing reconciliation. However, the US Govt fiscal year starts in October, so I'm not sure that January is necessarily a fiscal deadline - rather, it's a political one. Everything will be pivoting to the midterms in January and there will be no will for this.
Not passing BBB bill would be seen as a pretty big failure on the parts of the dems, do they really want to go into the 2022 mid-terms without having passed their "signature" legislation? I think they would be just as motivated to pass it in Jan as in this month.
Whether or not they can get manchin and sinema to follow along is another issue but I still think there will be a lot of house and senate members that WANT to get this passed, even in January so they have something to highlight to their constituents going into the fall.