I did a quick search and couldn't find an answer.
I wonder if part of the disconnect is that they are using just a general "dwelling" in CPI. As opposed to price per square foot. That is, is dwelling size shrinking, while costs are growing, this could cause housing costs to be understated in CPI
Lower population in of itself is a good thing.
It's the change that is disruptive and will cause suffering in ways that are unique to the suffering caused by over population.
As population growth slows, the younger generation needs to support more elderly. Which means we need some combination of:
Working population being more productive. Population making do with less.
However you approach it, there will be segments of the population that are very unhappy.