Those who advocate for traditional lifestyle are often asked that question. Now, first of all, there is no country on Earth where some women don't work, with the probable exception of Afghanistan? Not really sure what's going on there.
The question is really a straw-man and a typical example of arguing in bad faith.In every society there are women who aren't suitable to be wives and mothers, the types who used to become nuns and pr8stitutes in Middle Ages. In later period in Protestant countries it was mostly unmarried women who worked, according to the statistics I read, about 50% of single women in the end of the 19th century used to hold a job, and some married women too, though few.
So it's true that some females always worked, what changed is that now every woman, including wives and even mothers of small children is expected to work as well, at least part-time. We are told that the society will collapse without their input.
The point is, how much female labour do we really need and who used to do all these jobs before? 10 years ago I hardly ever saw a female paramedic. 20 years ago they were non-existent in my area. Now every single ambulance has a woman in it. Who used to perform this job in 2003? Well, you guessed it, men! Just like there were only men bus chauffeurs, male veterinarians etc etc.
Since their wives, mothers and girl-friends started working, men in my country significantly reduced their working hours, started retiring early and spend their 20s getting often useless degrees. Anything goes as long as they don't have to exert themselves in the workforce.
So the answer to the question above is: men. If the majority of women go back home than men will have to take over and start working full time again. One could argue that some professions are uniquely suitable for women, such as daycare workers. In fact, there is already a push in countries like Germany to have actual males work in daycare changing diapers. But really, nobody would even need daycare if mothers stayed home with their kids.
A society could probably function perfectly well with only about 10% of all women working. And most traditionalists would be fine with that.