The thing I like about this media origin theory is its missing link. We have no record of this theoretical prehuman medium. A marked trail is temporary by its nature, it could not survive the passing of its landscape. But prehistory has many such concepts, mostly unsupported by evidence. But we believe in the concept of protolanguage anyway, because it's very hard to believe that human grammar sprang up suddenly out of nothing at all.
Primitive people have extremely complex languages.
The only primitive languages we have belong to brain-damaged people. Or, to the spaces between established languages, the broken world of pidgins and creoles. In a generation at most, it becomes a creole, and in a few generations, it becomes a thriving mongrel vernacular, like English. The deep past is full of theoretical phantoms. Interestingly, the marks of landscape seem to be preserved in Nostratic.