But because it's grounded in the 70's they actually don't have that technology yet. Getting fairly close these days though. What were headsets like anyway in that period? Being an 80's kid we had tthe adjustable earmuff design that was held together by a piece of thin tempered metal to make it stick on you're head. Those cassette days... Lol.
The notion of "low fi sci-fi" and using elements from 1970's technology is an aesthetic choice, not extending to the function of an object.
Otherwise, there shouldn't be any gravity generators, plasma torches, or motion trackers either.
I think you can see how her headset looks here, looking pretty similar to the ones the Nostromo crew used (like in the scene Dallas dies in the vents):