Unless Dick Smith intends to fly solely within the Australian FIR he may have to take his challenge to the authorities in Hong Kong, Singapore, Vietnam and Indonesia as well given that they are also implementing ADSB requirements (whether it be on some specific routes or the entire airspace varies for each) on the same date.
ADS-B Coming Soon To Asian Airspace | Aviation International News
I can believe that some manufacturers probably have been dragging their feet in regards to designing or implementing equipment for their aircraft given that for some reason the US are not mandating ADSB until 2020 (probably because they have good radar coverage across the entire country) so this has led them (the manufacturers) to be complacent on this issue. But this means the issue is with them, not ASA, CASA or any other aviation authority that is implementing ADSB requirements. If this affects you, in my opinion you should have been making as much noise as possible to the manufacture leading up to this event (I acknowledge Dick Smith and others may have been doing this) not crying foul at an administration that has given all plenty of notice.
IFR aircraft (not VFR to my knowledge) operating below FL290 are not required to have ADSB fitted until Jan 2017 so plenty of notice there to research, source and fit appropriate equipment to those aircraft. I have flown King Airs (not Pro-Line equipped) and Caravans that have ADSB fitted and the equipment used to do this in my opinion is not outside the realms of any light IFR aircraft (Garmin GNS430W and Garmin GTX 330 with ES).