Discoveries like this can be both beautiful and disappointing. They help to refine theories and show us what is and isn't working, but they can also disprove theories we really liked. But just because a language doesn't actively use something doesn't mean the "universal" rule governing it is meaningless. If the concept can be understood, wouldn't that imply the construct exists somewhere in that person's brain.

It's been a looooong time since I studied linguistics, so excuse me if I'm a little rusty regarding Chomsky's theories.... I still have his "On Language" sitting on my shelf, maybe it's time to finish it....

Historical linguistics and universals are what make linguistics so much fun.