Just like student loans created the monster of exponentially rising college tutiton, it seems reasonable to suspect housing subsidies as a big cause of unaffordable housing (in addition to perhaps zoning laws).
It's confusing that it seems like more than 1% of the population in a given area are buying houses that demand you're in the 1% of income to be able to afford; until you realize there are no restrictions (or easily circumvented ones) on foreign ownership. There are LOTS of wealthy people in the world.
Has way more to do with lack of new development and the massive increase in costs to build new homes because of ridiculous housing laws. Look at all the cities with high housing prices and look at how few of homes they built in the last 30 years.