How do you compel private for-profit businesses to sacrifice profit for "cheap and fast"? Things are a lot different than they were post ww2, so it's an apples and oranges comparison to make today.
The only way you accomplish that today? You have to throw money at them to make up for those lost profits, that's the only way. So is the federal government willing to pay say, $500,000 per house to compensate builders for building $250,000 homes instead of 2500sqft homes that they can sell for $800,000-$1m+ instead?
If they want to legislate homes are cheaper, good luck getting homebuilders to actually build anything. Again, I'm not sure with PP's magic-wand plan is here aside from yelling about it endlessly and making people believe he's got some magic wand solution, when in reality, that doesn't exist.
Again, there's no magic solution to this unless the federal government is willing to get into the homebuilding businesss,
and the observant have seen how that pans out in the long term when even the province gets into the homebuilding business.