Cmon we humans know best that it is impossible to save junkies from impending death, even in nonhostile environments. Koalas should think twice before trying eucalyptus leaves for the first time or maybe someone put it into their drinks. To make matter worse those trees are highly flammable and explosive. Koalas made some bad choices in life. Don't worry, we will always have Koala Lumpur.
Koala is one of two animals we cannot save in case of natural disaster even if we wanted to, the other one is sloth.
Edit: For those who think I am an insensitive prick who does not care about animals, this month I had to hold a funeral to one pretty awesome turtle which had misfortune owners did not care enough about him/her and did not provide proper living conditions. I tried to save it but it was too late. Please do not buy pet turtles unless you are serious about it.