For the Seattle metro, yes, but that includes least pleasant places like Federal Way. Due to the endless torrent of software money, the ever-increasing demand to live here, and the seemingly insurmountable opposition to putting higher density housing in the city the trendy areas of Seattle are turning into San Francisco, another playground for dissonant yuppie fucks like me. I’m amazed you can live in Ballard at all as a restaurant manager at all; I’m impressed.
The days of Ballard as middle or working class haunt for Swedish fisherman are sadly long gone.
Price is supply vs. demand, not just demand, with an extra scaling factor for how much extra it costs to support people as population density goes up. The scaling factor (harder to build sewer lines, have to hire more cops per capita, etc. boring stuff) is a notable contributor, but it’s not the big difference. The overwhelming difference you see in the US in cost of living is land prices, and the overwhelming difference there is the income people have to buy the land vs. how much is available.
From there, income is determined by what it takes to hire someone, and the big variance regional variance on that is again, land prices. So you end up with the difference in income for, say, software developers between Michigan and Missouri being disturbingly close to a proxy for land prices, with the remainder as a “desireable place to live” bidding war.
If you want to define middle class sure, you have to work in cost of living there a bit; the middle class in North Dakota probably makes half what they do in manhattan. There’s real limits though; you don’t get a $100k dual-earner household in Seattle as the starting point of middle class, it’s heading towards the upper end just based on the sheer large number of people who earn less. The top 20% of households starts at $125k, and the top 20% cannot possibly be middle class unless you completely redefine the term.
$100k doesn’t feel rich around here, because your house is really not going to be anything special due to the ridiculous amount of money trickling down from the software boom and the tight land restrictions. You can buy nice stuff in every other goods category though, and you’re probably not going to have a debt problem.
If you’re unemployed and stuck in a high-cost area I’m sure this is all grating and I’m coming off as an asshole for telling you you’re better off than you think, but I’m not trying to do that, my apologies. If you’re talking about the US income distribution, though, it’s all pretty relevant.