> the price rises
ah, the swirling anonymity of "market forces"! These are all active decisions made by people, not forces of nature.
You're not wrong, of course, but it's worth looking at it from another angle. A house for a dual income family does not cost more to build than a house for a single income family. In a world where housing is considered more of a human right than an investment vehicle prices could have stayed low, more could be built, faster. Instead we live in a world where everyone must work more in order for their quality of life to stand still. I think it's permissible to be angry about that.
It doesn't take houses to be considered investment vehicles by anyone though for this to happen (even if some people do). Just more and cheaper money available to throw at the same things.
No such assumptions are necessary or intended. It doesn't make sense to assume working women produced nothing. I have no idea whether the construction industry took on more workers or not when women joined the workforce.
Regardless, most couples tend to buy one house, and two people's incomes can outbid one person's. That is all that it is necessary to assume.
For housing though, the economic unit is the household, not the individual, and land and location are not really affected by how much stuff we can produce. So housing costs will always occupy a large fraction of household wealth, no matter how wealthy we become.
Houses could only be priced such that a single income could buy them when most women did not work. Or nobody could buy them.
Once you have couples competing to buy that same housing stock, it becomes increasingly hard for a single income to compete and the price rises to match what the market can support.