This can work in some places (mostly looking at the prairies), but will do close to zero in others (like eastern Canada+BC). The simple problem is that the land the house is built on is often worth something like 80% the cost of buying property. The cost of a new house can be zero, but that will do little to help people afford new homes. Only slightly better than the tax cuts PP is proposing, which will have just as weak of an effect helping those who don't already own six houses.

The solution is to use the land we already use for homes more efficiently, and the only way to do that is to build condos and apartments. Make them mixed use and you can add the rental fees of a grocery store and several other services to the mix to subsidize the cost even further. A single grocery store that'll take up half the ground floor paid something like a million in rent a year, and that was before COVID. Add a convenience store, a couple fast food restaurants, a bar, and a dentist or salon, and you've got a mini-mall that'll rake in several million in rent that has a captured clientele in those that live above and near them. And that number will be in the hundreds for a 30 story apartment in the space of half a city block, since there'd be more than ten units per floor, even if it only has two-four bedroom units.

Such buildings can't be built in a factory, even partially. Not if we want them to last more than ten years, since that's the problem with the quick condos China tried to build.