there's also other issues that are sometimes being quoted, such as: housing being seen as a commodity, housing being held by a few big house-owners. but i'm not convinced that that alone could cause prices to skyrocket.

if there's a whole lot of developers trying to gain from housing economy, then there would be more houses being built until there's more housing supply than demand, then prices would go down again until they stabilize somewhere. but that doesn't seem to be what's happening.

sometimes, the city and community are called responsible for keeping land area expensive (by not making more land area available to be built on). this probably varies geographically, and i find it quite hard to believe that communities around the (western) world would not have realized this one simple trick to make houses more affordable again. so i guess there's more to it.