He is not far wrong. You don't need $10k pm to survive if :-

1. You are single
2. You are staying with parents, and don't need to help with the housing loans
3. You are married, but without children, no maid and no car

But if you are married, have children, stay on your own with housing loans to pay off, and a car, a maid, you will need $10k pm to be financially comfortable.

My family is a mature family meaning my children have already graduated, so I know what it was like to bring them up to that stage, sponsoring them through their studies, having a family car, having a maid to help out, paying for our housing loans and still have money for yearly vacations and retirement savings. Our family expenses hovered around $10k pm for many years and in fact exceeded that amount when my children were in the unis. And we don't live a lavish nor luxurious lifestyle!