So if the median household is “surviving” someone making twice as much (your typical mid level “enterprise developer” in any major city in the US) can’t thrive or someone working at Twitter who is making three times as much can’t save?

I'm saying everyone's situation is different and unique, and it is conceivable that someone making 3X the median income may not, even with effort, be able to save, just as it is conceivable that someone making 1X the median income may, with effort, manage to save go-to-hell money.

They aren’t able to save because they made different lifestyle choices than the person living in their same metro area making half as much .