"Narrow and cheaply built" isn't enough to make houses affordable in an age where crack dens with busted utilities go for over a million dollars. The ability of material to become cheap is capped far below the ability of location to become expensive.
google sez: "The median home sale price in Seattle is approximately $853,000 to $879,000, depending on the specific neighborhood mix and recent monthly data. Listing prices sit slightly lower around $750,000 to $775,000, placing Seattle among the highest-priced major metropolitan housing markets in the United States."
I assume a crack den with busted utilities would go for less.
I've lived in this area my adult life. Pretty much all the open spaces and lots have been infilled with houses over time. Prices go down the further away from the business core. Being within commuting distance to Microsoft comes with a big boost in price.
