They have symbols for languages that _have_been_ obsolete for centuries, if not millennia.

Also, if popular, these kinds of things tend to outlive their technology. For prime examples, look at http://graphemica.com/, http://graphemica.com/%F0%9F%96%AA, http://graphemica.com/%F0%9F%96%AB, and http://graphemica.com/%F0%9F%96%AC (to be fair, I think that is overdoing it)