I don’t know where you get your facts from but the koala was declared regionally vulnerable in SEQ in March 2004 after scientists proved that over 30% of the koala population had died in a decade. A major koala survey was conducted in 2001. Subsequent surveys done in Redlands (the Koala Coast) and Moreton Bay Regional Council were done in 2007 and 2008. These were conducted in the same areas as the first surveys and the results compared.
In addition, annual surveys were conducted in the above regions every year. These statistics were submitted to local, state and federal government bodies. What came out of the statistical analysis was that an additional 67% decline in the koala population occurred in Redlands (the Koala Coast) and a 47% decline in the koala population in the Moreton Bay Regional Council area since the surveys conducted in 2001.
After the fires in Victoria and South Australia I would posit that koalas are no longer common anywhere in their natural range. This is not the view of radical greenies or rabid environmentalists. Scientists from the University of Queensland and the Queensland University of Technology have confirmed these results.
You are absolutely wrong, the fires did little damages to the koalas in South Australia and koalas are still very common.