"We would love to build more affordable starter homes, but when high-end homes cost the same to build and are far more profitable, we lose the incentive to build smaller units,” said Isaac Stocks of Azure Northwest Homes, a Seattle-area home builder. That sums it up. Plus, more expensive homes means more property tax revenue, so there's little incentive for state/local gov to encourage lower end housing. Finally, it…
As for cities, yes. They like the house pricing go up. It helps with school budgets, particularly. Then it goes into positive feedback loop with better schools raising house prices, too.
For cities like seattle, it's not hard to see houses in different price bands (single tech earner, couple tech earner) and so on. Hard to find a solution, unless the big employers diversify their locations.