your major problem is that, although what you assert used to be the way allowances were considered, modern generations of pilots and cabin crew use meal allowances to inflate their income when applying for loans. Nowadays, the ATO, banks, employers consider meal allowances to be income. All that is different is that there is a certain amount that the ATO considers to be tax free.
the horse has bolted. A long time ago on this issue.
1) If anyone isn't doing everything to maximise their affordability profile when applying for loans then they are clinically insane. Of particular note there is Qantas' nasty habit of contracting as opposed to full time, only full time workers get easy access to home loans.
2) Whether allowances are considered income or not, they are generally spent on exactly what they were designed to be spent on. Living when away from home.
3) Is there a point to your interest in allowances? Will it help get Qantas back on track after years of neglect? Will it help any 73 be inspected for wing cracks any faster?