Could it be the promoter of this event? Or the TV deal for this event? Listening to a few posters here - competitors wanted to be at V8SC events. Well here you go - look at Barbagello, Townsville & Sandown.
Or could it be as simple as mechanical or accident damage over the last 9 months? Reference a Speedcafe article not 3 days ago
Reality is - Australian GT has raced across 3 different series in 2017 (4 if you include the B12HR) and probably attracted in the vicinity of 40 - 45 different entries/competitors across the year.
Could it be as simple that running unique Sprint and Endurance Series might not be the answer?