But if a market is unfair and dysfunctional then housing will still be unaffordable even if it is over supplied.
Imagine I owned all the land and wanted to maximise my rental returns. As the aggregate rental value of land results from the efficient exploitation of agglomoration effects on one hand(development) and a preference for spending on locational amenity over alternative goods and services on the other(preservation/enhancement), I’d want to make sure everyone has the buildings they need, in the right places. And those places to be as pleasant and well planned as possible ie optimal resource allocation.
But, as I would now be collecting all those rental values, my income would increase by a trillion dollars a year, while everyone elses would be reduced by the same amount in aggregate.
Making housing(among other things), exceedingly affordable for me, but more unaffordable for everyone else.
The unequal distribution of land rents is the only thing that makes housing unaffordable for typical households. And the selling price of land is nothing but a measure of economic injustice.
If more housing gets built where demand is highest, house prices and rents go up. Because the as margin of production shrinks, demand goes up and land is irreproducible.
Peoples educational credentials often narrow their perspective. Economics being the best example of this.