Any definition of the middle class that doesn't include the middle of incomes seems wrong to me. Median means half above, half below, how would that not be the "middle" class?

Where did you get the $31k as the median income for Seattle? This source says it is closer to $95k?

https://www.seattletimes.com/seattle-news/data/seattle-media...

I took the national median per capita income. Looking at King County's per capita median income puts it closer to $46k. [1] I also suspect I low balled the housing and medical insurance costs.

[1] https://www.census.gov/quickfacts/fact/table/kingcountywashi...