Dick,
There's currently over 500 entities holding AOCs in Australia authorising Charter operations in Single-Pilot certified aircraft (B1900, Metro 23 and down).
Of those, 23 hold AOCs authorising RPT operations in single-pilot certified aircraft.... Hardys, Chartair, Aviair, Corporate etc.
Everyone currently operating a Grand Caravan, a B200 KingAir, a Bandierante or a Metro II on Charter with more than 9 passenger seats will jump from Charter straight to Part 121, same as Qantas. The vast majority of those organisations will disappear.
Everyone operating 9 seats and below who does not have an RPT certificate or >10 full-time pilots will not survive.
If Parts 119, 121 and 135 are enacted as made I predict there will be less than 50 General Aviation Air Transport AOCs remaining in 2022 from the 500 today.