If you spend a third of your income on housing and 8% on healthcare [1], then those components–assuming your 5x and 7.7x multiples–will raise your cost of living by 2.25x. That leaves 1.75x for the other components (to get to the overall 3x). That sounds reasonable as a median estimate.
> if personal spending is weighted towards healthcare and housing (anyone who rents or pays a mortgage below a certain income) then your purchasing power is declining faster than the real wage would suggest
Sure. If you spend a lot on imported dates, your purchasing power will currently be declining faster than the median American's. This is a problem. But it's almost by definition not one that can be widespread.
> the "real wage" is inflated relative to the lived experience of those people
Well, yes. There are regional CPIs and income-indexed CPIs and all manners of privately-calculated costs of living. Paying attention to lived experiences or whatever is important, especially in politics. But it's no substitute for broad measures when conducting a national economy.
[2] https://www.bls.gov/opub/btn/volume-9/how-have-healthcare-ex...