If I'm stating the obvious, Centaurus, it's because you seemed somewhat oblivious to it. CASA Manual of Standards Part 139 - Aerodromes is crystal clear when it comes to the purpose of the Runway End Safety Area.
"A RESA must be provided at the end of a runway strip, to protect the aeroplane in the event of undershooting or overrunning the runway ..."
So, while
your focus might be on high speed emergency stops that is most assuredly not the whole discussion.
You are advocating a solution that augments one of the the stated purposes of the RESA while simultaneously prejudicing the other, and prejudicing it in a manner that would endanger lives. And if you want to have a look at materiality, the ATSB has handled more accident investigations relating to undershoots than overruns.
And just by the bye, Derfred, the major cause of undershoots is weather; variable and gusting winds and windshear, in particular. Near as I can tell very few airports are exempt from those conditions.