Just imagine the Greens and the animal libbers reaction to mass kangaroo slaughter. I have to get annual permission to reduce the numbers when they reach pest level. Kill 100 ( my annual quota) and the numbers making a nuisance of themselves drop off dramatically. I doubt if the total population in Australia would supply the demand for red meat for more than a few months if it was all that was available.
Remember that saying "meat eaters make better lovers". Maybe turning vegan will help reduce the world overpopulation. You first, I don't mind being last.
The kangaroos may fight back. I was once chased by a large roo. I was on a motor mower when the roo came at me. I baled out and it kept attacking the mower. I won in the end with the help of a 22 magnum. ( must remember to put that in my book.)