I still know quite a few people that have some form of breadwinner/homemaker deal going on - that's the late 20 to late 30 bracket mostly. As soon as kids enter the picture, I'd estimate a majority of people in my field of vision, actually. Quite often the mother - sometimes the father - will work a part time job while kids are in kindergarten or school, while the other partner will work full time. For some people this is an economic necessity, other people do it because "just being a homemaker" is too boring and unfulfilling for them.

Given that the average number of kids per family goes down, the age of when people have kids goes up (and a later age usually means a more sound career/financial situation), there are a lot of somewhat affordable options for child care, and technology makes life easier on a whole[0], the effective work a "homemaker" has to do may have gone down significantly over time, at least for the "middle class" and better.

The part-time-breadwinner-part-time-homemaker partner would still have worse prospects in the fulltime job market after a split up, and those part time jobs usually do not come with a career track either.

[0] My grandparent's gen couldn't afford a washing machine when they were young adults, my parents' gen couldn't afford amenities like a dish washer or tumbler when they were young.