Where the government insures most of the mortgages against default, rather than lenders assuming the risk.
If the zoning allows building higher density condos and townhomes, the market will just increase the prices of condos and townhomes to meet the lower/entry level end of the market, instead of that share of the market going to smaller single family dwellings.
Higher density housing for sale rather than rent, just increases the profits of developers per acre of land.
Higher density housing outside of downtown cores reduces space for gardens, parks, yards to play in and increases traffic and demands on infrastructure such as water and sewer systems.
Affordability becomes redefined as buyers being able to qualify for enough debt to buy a condo at market prices, rather than using government regulations, and the removal of government subsidies and supports to force housing prices lower so that median prices are in sync with median incomes.
Instead, I favour strategically planned urban sprawl to create traditional family neighborhoods of single family dwellings, with condos and townhomes limited to the downtown core for homebuyers that want a more walkable lifestyle. Public transit corridors from downtown cores to the suburbs should be filled in mostly with rental housing/apartments. The more rental housing available, the more competition for tenants, which should keep rent prices lower.