Except it's not, building costs are relatively fixed per square foot, but it's more profitable to sell them in one and two bedroom units, then using the extra space for a third bedroom. This is why in almost every high density building project you only see one or two bedroom units. Because that third bedroom isn't going to bring in as much money as an additional one bedroom unit. The result is the only place you build those kinds of houses are out in the burbs, it no more cost effective it's just that no one would buy a one bedroom house in the middle of no where so they build the only thing that will sell on the quickly diminishing resource of undeveloped land. Since we have been doing that for sixty years the only undeveloped land is well outside any reasonable commuting distance to a job, so you end up with house prices in the previously developed location soaring, then when the idea that maybe using up all that space on low density housing was a bad idea the response is there is intrinsic limitations.

And this goes back to the title of this article, part of the reason people see parenting as so burdensome is they now have to deal with the added realities of a Civic planning policy that is a miserable failure.

Edit: To add data, to build a basic house ( 4 corner ) at a Good, but not luxury level averages $147/sq.ft. , to build a multistory residential unit at highest quality it averages $150/sq.ft. If you build over 15 stories the average price can drop by about 11%. Those are raw construction costs, including labor and materials, and take into consideration most new housing developments in the suburbs are _not_ basic 4 corner houses.