A low-cost battery-backed (operator replaceable), low-current-draw ATSB-Out device + mandated tablet with OzRunways (or similar) with ADSB-In with mounting for all aircraft would crap all over all other safety measures.
Cost? Say $2000 per aircraft installed. Estimated 2 hour install time.
15304 aircraft on VH register. Total cost $30 million.
Smart country? Surely we can do it?