Nobody ever asks the question: If the democrats are all about affordability...then why are places like Seattle and San Francisco the most expensive and least affordable cities in the USA?

People do ask that question. I mean, it's hardly a secret that blue spiky global cities are expensive places to live. That's a criticism that gets thrown at Democrats a lot, and which progressives often ask themselves.

Democrats usually answer, "demand." Seattle and SF are attractive places to live and have massive economic engines that create a lot of wealth. Amenities, good climate, proximity to high-paying jobs - and a vibrant history of being culturally engaging and interesting places to live. Of course it's going to be expensive to live there, just like it's expensive to live in the most desirable parts of any country.

I suspect that answer doesn't satisfy you - and I would agree. I would argue that "supply constraints" are an equally important part of the equation. Some are geographic. You can't make more land in cities like San Francisco, where there's a lot of natural features and of course the coastline that limit how much land is available. But some are regulatory - increase the density and make it easier to build, even in the "charming" parts of town, and you'll bring down prices.

But regardless, it's not a question that Democrats never get asked or have never grappled with.