Starlord, we do.
But what does it give me? How is it safer? A pair of aircraft heading away from me, I can't tell if they are getting closer to each other, I can't tell if they are getting further apart (until one of them turns). I get a better idea of that from my radar, with Mode S airspeed, groundspeed, Mode C altitude.
I look at them out of the window because I have to. I look at them on the radar to see their relative positions and speed, which surely is the safety critical thing.
That's what I mean by outdated.
RSVA developed as a concept when control towers had no surveillance capability.