Single unit structures (red line) are the story of the moral panic of the 2000s. We have closed down mortgage markets, removing the main source of housing expansion in the country as a whole. This remains at levels similar to the darkest brief recessionary periods of the past. The red line is the answer to the question, why has the recovery from the recession been so weak?
A while back, I was ready for a treasuries/housing trade as the inevitable recovery of housing would coincide with rising interest rates as capital was redeployed into real estate. But, I have lost faith in that trade. I see few signs that either of these problems will be solved before the Fed errs in the direction of contraction. I would love to be proven wrong.
I suspect that the trade will come eventually, in a slightly different flavor. There will be a recession where housing performs relatively well. Maybe instead of taking a long housing/short bonds position during a surprise recovery, the initial position will be long housing/short stocks/long bonds during a contraction. It depends on how it plays out. In the meantime, a highly leveraged position as a direct owner in low end rental units is probably the most lucrative place to invest in any context.