In those days you couldn't have (on your professionally produced, mainstream, mass market TV show) a woman who didn't want to be a housewife as a main character on your show unless that was portrayed negatively or being used for comedy. These days you can't have a woman who wants to be a housewife as a main character on your show unless that's being portrayed negatively or being poked fun at.
Por qué no los todos?
Is that really true though? If you mean that you can't have a houswife as a character on your show that very obviously isn't true. If you mean you can't make a show where a character aspires to be a housewife, I'm not sure I understand what the narrative purpose of such a story would be. Becoming a housewife isn't really an aspirational achievement in the way having a prestigious career is, and I don't think it's a story many are really interested in, nor one that would be easy to tell in a manner that doesn't seem forced. There is certainly a lot of media (both in the past and today) where a woman aspires to romance or marry someone, and domestic fantasy is a common element in those, but that isn't really specific to becoming a housewife, and the romance is the key aspiration in those.
It also doesn't help that maintaining a family on a single income is not economically viable for most people anymore. People want stories that relate to their own fantasies.
This is not a true statement for many folks out there, and there are plenty of people who can relate to stories of being in the home. I think the best answer is broadening the things that are acceptable to aspire to, not opening one door while simultaneously locking another.
That is actually the premise of the ABC show "American Housewife" which has run for at least 5 seasons (the main character is a housewife, and does not aspire to be anything more than the best housewife she can be, because she sees it as just as fulfilling than--or even more fulfilling as-- being employed in the workforce.)
If you want a return to the sanitary, saccharine dom coms of the sort the Simpsons was originally a parody of, I have to vehemently disagree that there is any real desire for that.
Now the moral panics are in the upper income left, and they actively try to get you fired if you trangress and all of a sudden it feels a bit restrictive in that environment.
Also social media makes average people significantly more vulnerable. Drunk comments would stay drunk environments outside of work comments, now drunk FB comments on a public group can get you fired.
I see people pining for this forgotten past time a lot, and it makes me realize that none of them remember or think the same way of things like the satanic panic, moral majority, etc, let alone remember the times when people got offended over the mere suggestion of an interracial couple or a woman who didn't want to be a housewife. Oh the scandals that would occur if basically any program run today were to be broadcast then. They don't remember the Television Code or the CCA, nor did they grow up on a diet of classic Hays-code era films, dripping in extreme sensitivity.