As far as I understand some serial protocols use RS485/422 differential signalling to be immune to noise for long distances. We also know that differential signalling is about voltage levels and inversion i.e. it has nothing to do with the protocol itself.
Now I'm wondering why I2C communication link not extended by using two RS485 transceivers. I never saw any example of it. Is there a particular reason why I2C is always single ended?