How do you figure there is enough housing?

CMHC thinks we need 3.5 million more units by 2030 (bringing us from from a projected 19M to 22.5M) https://www.cmhc-schl.gc.ca/professionals/housing-markets-data-and-research/housing-research/research-reports/accelerate-supply/housing-shortages-canada-solving-affordability-crisis