You can do almost any job with almost any degree.
If you're a typical white-collar professional in say some business/science/engineering field you'll typically, unlike nurses, live somewhere with abundant other high wage jobs.
There’s a lot of white collar work that only requires a nonspecific college degree, but I’m not aware of such a high demand for for HR staff or accounts payable specialists.
Salary for nurses varies widely, and in some places, they're wage-competitive with Amazon delivery drivers now. I can easily see people deciding that even though they like helping folks, getting paid less than the people who drive around and drop packages all day doesn't seem like a fair deal.
Men making less than the median for their gender (something like $55k in the US) are still marriageable; plenty of women marry men who can’t support families on their salary alone. Even at the median salary, supporting two people — let alone a larger family — could be a struggle, depending on debts and other commitments.
And then there are women who are not married to a man who makes money, either because they remain unmarried or because their husband has lost his job or cannot work for some reason.
Further, even if the cards align, it’s not great to be in a position of dependence on your spouse's salary. Sometimes you have to split up and sometimes your spouse dies without leaving significant insurance or inheritance.
