Well you're kind of right.
But I can buy a 6,000 sq. ft 6br/6ba mansion with a basketball court for about $500,000 in the midwest. Out in the country, about an hour out of the city. There are some really insane deals out here if anyone really had the money.
That same house in LA (in the right area - west LA, the hills, Los Feliz) would be $4 million at least. In SF? Turn into three 2br condos at $1.5M each if it's in a cheaper area, otherwise leave as is and sell for $6 - 10 M.
A $500,000 house might cost $3,000/month mortgage + taxes, all in. $100,000/yr could get you there in the midwest.
If you want that same house in SF, you'll want $36,000/month to spend on a mortgage. I guess you could get by on $43,000/month take-home, which would be $800,000, maybe $900,000/year.
It really all depends on what you want. No, a mansion isn't a must. But you can take a step down - $230,000 is enough for a nice 4,000 sq. ft. house in the midwest (small but nice town). If you're making $80,000/year, you can easily afford that. If you want a big house or land, then yes it keeps scaling.
TL;DR depends on the mix of goods you want - cars and food --who cares, about the same cost anywhere. Bigger house? That's where the money matters. As big as you can imagine, at less than $200/sq. ft for very high end finishes. It's not prime location but not everyone wants prime location.