[mlac]

That works until the bubble pops, and then really only for for families with high incomes. In your example, let's assume its 70% of take-home (it has to be after tax, or they would literally have nothing left). Taking home 300K, it's easy to live off of 90K. Taking home 100K, it's harder to live on 30K a year. Taking home 65 and doing that, it's not going to happen.

The cost of most household consumables is largely fixed, even as income scales. One can have expensive taste and increase that, but you can only spend so much on toilet paper and laundry detergent.