This article recently published by the Oregon office of Economic Alalysis talaks about the importance of housing supply in Oregon. In particular there is a good section on the affordability issue in Portland, in particular the last graph shows our issue...  no builders can afford to build in the lower 3rd of pricing, so its hard to buy a home as a rental.  There are many reasons for this...  For one when I started as a Realtor the City of Portland charged about $2,000 for a building permit and you could get it in a few days. Now, its just under $50,000 and it takes almost a year.  In addition to this the cost of lots has gone through the roof.  There are many reasons for this too; builders leaving the business in the recession, developers also leaving the business in the recession, a huge delay in getting new lots and subdivisions approved, and of course the large influx of residents to the Portland area.   You can view the entire article here... https://oregoneconomicanalysis.com/2017/12/14/why-housing-supply-matters/