Interesting comparison with Tescos, thewisealderman. However:
1. If there is an incident at Tescos, an ambulance can be there in minutes. If someone dies there, the ambulance comes and takes them away. They're not forced to work around the dead body and cope with relatives and traumatised passengers for an extended period. I won't deny Tescos employees will from time to time have to administer first aid. First Aid, however should not be confused with Aviation Medicine.
2. They sleep in their own bed at night. If you sent a Tescos employee to Australia for 9 days, you'd have to pay them some sort of allowance and cover expenses.
Don't get me wrong, I'm not putting down anyone who works at Tescos. I've worked at Sainsbury's and it can be hard work. You are often dealing with drunks, theives, chavs and drug addicts. Customers treat you like crap and it's not as though you can have them offloaded.
You can compare the cabin crew role with many other jobs but unless these jobs involve some sort of travel away from home, you can't really compare wages AND COSTS.