Affordable housing definition is typically 30% of gross income, which for a minimum wage earner in Ontario is about $860/mo, and for 2 earners $1720/mo.
The tough part of affordable housing is defining housing through the lens of entitlement and necessity. Does a single person require a 1 require a studio apartment or a room in a house with shared facilities? Does the purchase price of a home get included in 'affordable housing' or is it a measure applied to rents?
If I were solving the problem, I'd do many things, but the first would be to increase low-income shelters by building lots of small apartment buildings with simpler designs. For example, building small walk-ups of 6 stories or less to eliminate elevators (making 1/6th of the units, the ground floor, fully accessible. Make more use of shared facilities - laundry rooms, community room, and for some portion shared kitchens and bathrooms like you find in student housing.
An example like the one below, would fit nicely on this lot
https://www.realtor.ca/real-estate/26234623/385-centennial-rd-toronto-centennial-scarborough and could be built in prefab form for $250/sq' which works out to a build cost of 3.5M or well under $200K/unit including land (but not including development costs). Go back to basic fixturing (kitchens and single bath, central laundry and community room in the basement, unit HVAC, and no elevators.
Fits on a 60x100'lot for high-density areas.
View attachment 66322