Wives went out to work, en mass, to mask inflation in the 1970s. And now you sometimes have marriages with 3 or 4 jobs, again to deal with Inflation.
Rat race.
Many people competing for the same jobs drives wages down. More than half of households are dual-income households.† This increases the labor pool, which drives down prices.
Ironically, it would seem that, if more families switched to one parent being the primary breadwinner, it would drive up the cost of labor and make single-income households a more sustainable proposition for more families.
The knock-on benefits from the additional time and attention the now stay-at-home or part-time working parents could give their children would have a generationally positive impact on well-being and prosperity.
† Bureau of Labor and Statistics: https://www.bls.gov/opub/mlr/2020/article/comparing-characteristics-and-selected-expenditures-of-dual-and-single-income-households-with-children.htm
Discussion
Most women have always worked (at something other than homemaking), outside of the postwar Americana Era, but it used to be more life-stage related and a lot of women worked in family businesses or side-gigs.
I see more of that, as people view work more flexibly and resumes become more random.
The "get hired by big company at 20, work full-time until 65, then retire and get a gold watch" Era is basically over.