If we follow your argument there should never be a loss of separation in the air when there is a radar available because the controller can see what is going on.
My arguement if there ever was one, was to show that there is a debris detection radar in Vancouver which would likely have picked up a truck sitting on the runway. I said
"Perhaps this would prevent this type of accident..."
and pasted the link.
For some reason you said
"punkalouver, I have never understood why some people continue to believe that installing radar and other surveillance systems will prevent runway incursions and accidents. At best they are tools that support those involved in airport operations."
So I posted an example of a potential accident prevented by ground radar.