I see you are very uninformed about the original caretakers of the Australian continent .. who very definitely cultivated the land so that there was an abundance of food safety for all. They were a lot more altruistic, also, about how they prepared food - leaving things in place for any forthcoming caretakers that would enter the region.
Every population grow to where they barely can support themselves, including Australian natives. It doesn't matter what you do, until we got good contraceptives starvation was a fact in every culture except after periods where food productivity quickly increased or population levels quickly decreased.
The only way to not starve is to not have sex, and no culture managed that well.
