SF snark aside, there are some parallels. Portland Metro's urban growth boundary[1] has both reined in sprawl and reduced the availability of cheap land for development. Combine this with horrendous traffic on the major suburban arterials (I-5, I-84, OR-26, I-205) and you have a sustained demand for close-in residential properties.

You could call this an "artificial constraint", but it's also part of what makes the Portland metro region a desirable place to live.

[1] http://www.oregonmetro.gov/urban-growth-boundary