It doesn't mean any senses how an apex predator that remained hidden for many hundred years as there are no competitors beside the tiger wolf and dingoes (althrough I doubt they would take on a Thylacoleo) and leaves no traces behind. You would think that Thylacoleo populations should increasing as there are more megafauna to prey on. (Camels, cattle, feral hogs etc)....yet there are problems with herbivores (including large kangaroos) being overpopulating in some areas, suggests that there are no Thylacoleo prey on them. Heck even feral sheep/goats existed there as they are easy prey items, yet nobody made a meal out of them beside the dingoes, pythons and eagles.