And it wouldn’t be even that improbable, in my opinion at least. In the end, in many languages the word “figuratively” was so overused as a stand in for “literally”, that it became it informal synonym (I know for sure that it is a thing in both English and Polish, but it is probably more widespread). If words of completely opposite meaning can be blurred that way, it wouldn’t be so strange for that effect to emerge as a case of euphemism.