Greentomato I agree with your original premise- it would be great if society were set up more in this way, or rather, that business and public sector were more open to the 4 day week idea like in some Nordic countries.
However, lots of people then came on and said that in fact they were already living in this utopia, which was mainly achieved through not being a wage slave/obsessed with work type of a person, and/or not placing such importance on material goods.
I think it's important to point out that I am not obsessed with my work or indeed fussed about material goods- I work f/t to RENT a house for my children, and we go on one cheap holiday to their other parent's homeland most years, usually borrowing to do so. It's not about rejecting multiple holidays and a bigger house- we don't have those things, and neither do many many people who work long hours and have to pull in two wages to survive (we only have one through circumstance).
Also, a lot of women already do work part-time in the UK, far more than men, because they are supported by men or supported by the state to do so. You could argue that it is in their economic interests to do so (to support the main wage earner or earn enough to maximise other finances such as benefits). So, in some ways, women are able to work fewer hours than men through gendered societal roles. I don't necessarily see that as a positive thing, though, if they can't use their qualifications/are under-employed/would prefer a different type of work than what is available around school hours.
I would prefer a more even gender split with men, but whether the men, who hold the economic power, want to downsize their lives and work 3/4 days and even things up with their partners is really quite questionable, in the UK at least. I do know a few couples who work on this model, it's not the norm.