For general kangaroo info, check out the red kangaroo post.
Grey kangaroos are smaller than the reds and need more predictable climate. Because they are more abundant that other types of kangaroos, the eastern grey can be “commercially harvested for export” by licenced hunters.
In terms of the keyword abundance, this is similar to how other cultures have viewed the whale and bison. A gift from nature which provides lots of resources and for which the community is thankful for. In this case, the grey kangaroo provided meat, pelts, and strong bones for digging. She is a sign of prosperity and a reminder that earth will look after you if you look after her. The balance of the planet relies on us taking only what we need.