The whole cost of living/purchasing power vs median income or gdp thing is quite regularized these days.
GDP and median incomes in international comparisons are cited, usually, as PPP - Purchasing Power Parity. In order to even out differences in price levels as well as exchange rates.
Its beginning to be done with US States also, because you are right of course, there are great differences between them, and they are very relevant. I have been doing this for many years now. I like the MERIC (Missouri Economic Research and Information Center) index for cost of living by state. Check it out.
Thank you, I will check out the MERIC index. It sounds very interesting and informative.
For years, I have picked up local real estate pamphlets whenever we are on vacation somewhere. I like to see how the housing prices are.