Yeah; I don't think it's *that* unlikely for it to happen again. But my own principal concern about this mirrors what somebody else already pointed out: the one-major-release-per-year schedule is not engraved on any stone tablets. So I don't want to go to a release numbering system that depends on us doing it that way for the rest of time.
We could you use YYYY as version identifier, so people will not expect correlative numbering. SQL Server is being released every couple of years and they are using this naming shema. The problem would be releasing twice the same year, but how likely would that be?