> ...relatively small increase in supply (say 20% over 20 years which is quite feasible) can have a huge influence. I think your framing of that number is a bi

> ...relatively small increase in supply (say 20% over 20 years which is quite feasible) can have a huge influence. I think your framing of that number is a bit wrong, we've been under building demand by orders of magnitude for 40 years. Getting the sort of increase that might make housing "affordable", e.g. housing at only 3-6x the median household income, would require construction on an impossibly massive scale over the next 20 years. To wit, the Sunset neighborhood in San Francisco has added 21 new homes since 2011. 12% of the city's land area has added just 21 new homes over the last decade. Generously 80 new residents of San Francisco, a city of over 750,000 people, have been added to 12% of the city's land area in a decade. The amount of politics, money, and boots on the ground construction necessary to make housing affordable in West Coast cities is out of reach in any "business as usual" scenario in my mind. We'll need a crisis, until then, the mountain will remain unmoved I think.