I live in a semi rural area and $84k today for a family of four will not exactly have you living like the Kardashians.
After taxes you have $800-1k for mortgage, $1k+ for health insurance pr month or more, $4-5k HI deductibles to contend with each year, property tax, 1 new car and 1 used car payment, reasonable yearly vacation for the kiddies, saving up for retirement in 401k and kiddies college fund, house and car repairs, food utilities clothes, kids activities
Not much left over. A needed new roof at $10k or $4000 new transmission will put many in the red for some years.
It can be done and many do it (in some areas) but it is tough.