In operators, our focus is how to USE tech for customers and make money.
I did a technical interview for a product marketing role with a hw vendor. The HW engineer didn't seem interested in my experience. He followed up with questions asking me to explain basic terminologies that engineering and I use on a daily basis w/ no need for any explaination. However, w/o script or rehearsal, one can't present well at interviews. Therefore it seems impossible to prepare for this kind of technical interview unless one tries to become a working telecom dictionary. And what is the point of becoming one?
That is how I concluded vendor marketing = technical writer.