FB,
TCAS ? .....its been around for some time now.
Yes that is true.
A couple of weeks ago I flew from Newman to Jandakot, identified at 300 odd feet, previously would not see RADAR till some time after Meekatharra.
Not all aircraft have or are required to have TCAS/TAS.
If all aircraft had that level of ADSB coverage, most of these near misses in Class G that Jeta108 believe to be unquatifiable, would not occur.
If every aircraft had TCAS, this would considerably reduce the chances of aircraft collisions in all airspace.
OR
If every aircraft had ADSB, this would considerably reduce the chances of aircraft collisions in a very great deal of Australian Airspace, provide pseudo RADAR coverage pretty much Australia wide (at 10,000ft), help from FW is just a button press away.
There is no silver bullet to combating the size of Australia.
TCAS plus ADSB in/out is the best option = lots of money.
If the choice is TCAS or ADSB, IMHO ADSB offers more benefits.