Several cockatoos have lived far longer than that - I know of one (sulphur-crested) who was 110.
I don't have a galah, but I've seen life-span estimates for a well cared for pet galah up to 80 years. Other estimates put the average closer to 50 years.
That's interesting. I did some more research and found the same range, some say 40 while others say 70 or 80. The Major Mitchell clearly can live to 80, and as you point out the sulphur crested lives considerably longer. However, the Goffin only lives to be 40 and that is pretty well determined. I don't understand the discrepancy in Galah estimates. Has anyone here seen or know of a record of a 70 year old Galah?