yet you've suddenly decided that the best thing to do would have been to bump this box (which you never even heard of until today) to the top of the list!
This box is common and already widely installed.
Though what would work better (cheaper and get to planes faster) is to have the civil aviation send broader military alerts when a transponder disappears. This one was "lost" for a long time because it wasn't acted on the moment contact was lost. If military radar was officially requested at that point, we'd likely be recovering bodies right now, rather than discussing what could be done to make airplanes more trackable. But the military doesn't run with radar on, except for known defensive positions, because it gives away too much information, but turning it on for an "emergency" would likely be acceptable, so long as it was like the plane lost at see once in every 5-10 years or less.