Probably because most of the men think they have to work to make money. So they choose to work. While their women prefer to take care of the household rather than work.
At some point you are correct but that was generations ago. The generation now of women are the working wives. I know lots of women working for their family so that the burden that the husband is carrying will be lesser. I know at least 21 women who are into the world of cryptocurrencies and most of them are wives.