They have been working on automated ATC for a lot longer than 20 years. I worked at Eurocontrol 1991-1996 where they had been developing a system called ARC2000 since well before I arrived. As the name suggests it was intended to take over ATC in Europe by the year 2000. I worked on a less ambitious system that helped visualise conflicts for manual resolution but that was not a big priority so I eventually left.
My internship in the mid-1990s was with a professor studying VR systems for ATC for low-visibility operation. At the speed this field changes (or doesn't), I doubt I'll see it in my lifetime.
I'm sure it would be done better if implemented over audio, but the image of a frustrated pilot yelling "REPRESENTATIVE! REPRESENTATIVE!!!" just came to mind.
