It is true that we are implementing ADS-B well ahead of the US (where the equipment is designed & made). Why?
Because the US has blanket radar coverage, we don't. The US is replacing radar with ADSB so the gains are minimal. We are replacing nothing with ADSB so the gains are substantial.
I have heard (I do not know first hand) that some of the airlines are not ADS-B equipped and are operating with exemptions. It would be interesting to explore this. If CASA are selectively granting exemptions, then we are back to CASA at its best and we owe it to ourselves to highlight this.
Yes, some of the airlines aircraft are "ADSB Exempt".
So is Dicks Citation. It allows the aircraft to fly above F280 in ADSB Exempt Airspace (very roughly the J Curve and the oggin).
It basically come down the the "greater good". ADSB only delivers its full potential if its exclusive. What the biz jets lose is less than everybody else gains.
are we making FL 280 & FL 290 unnecessarily crowded
However, this may be valid (pedant mode - its F280 and F270)
I do wonder if the powers that be have decided on a hard mandate so we avoid the situation of RVSM. Over 10 years later we have non RVSM aircraft using three times the airspace that otherwise would.