i think there are a lot of practical reasons for why this is happening that one needs to note before judging it:
with the rising costs of childcare & decreasing overall wages (relatively to inflation), it is a sad reality that a parent within an average wage range will often save more money as a stay at home parent then they could earn within a given timeframe. extra time beyond that can further save money with a DIY, ranging from cooking your own meals, maintaining your own house, crafting or hunting cheap deals for your own household needs, and even an increasing rise of vertical wall gardens with vegtables and spices, not to mention the art of coupons.
alternatively this can be split with both parents working part time, but lost employe benefits and a decreasing chance of advancement makes this unprofitable for the household as a whole.
why does it often end up being women?
i think more often then not its a matter of innertia, getting a stable job with paid meternity leave is quite difficult, getting your job back after a months of unemployment isn't always easy, so often the mother already is a stay at home parent, and in this economical times, it is just safer to keep the job.
another element is that women make on average less. the reason is quite reversed - for corporations women actually cost more, because the more women they hire, their company's legal insurance assestment is going to come up a more expansive deals, for no other reason then statistics, and the company that pays for the difference is going to pay it out of your wage. why? because another woman sued her company for sexual harrassment, because another women sued for not getting a maternity leave, because another women did crap that has nothing to do with you, but now your taking slack for it. the result is that if your not sure if you have enough money for bread next month, then those extra few cents on the dollars are worth a lot.
there are exceptions:
a woman can have a higher education then the men she's with, but since women tend to go for men of at least the same level of education and income level then they have, this is rare.
a man can immigrate for a woman, often a long process, and this happens more with the internet, but since men are a lot more likely to marry a second time (to younger yet to have married women) then women, more often then not the men will be the one with kids, and since younger women often marry older men, more often then not the man will have more job security then the woman, and the woman wil be the one immigrating for the man.
is this what i would go for? not IF i can avoid it.
my reasoning? ow feminism modern time and ideological blablabla bla blabla? nope, none of that. the simple fact is that if i started a family there's a good chance it would include a daughter, and if it includes a daughter i would like her to have a good role model that would incourage her own sense of independence, i can trust myself to always be there for my children, but not my far future son-in-law's. i also don't think its healthy for one person to be so much at the mercy of their partners, i know it wasn't for me when i was a stay at home dad, it wasn't only bad for me but it was bad for the relationship as a whole and thus for her, and i don't think it would be any less bad the other way around. there's a realistic dependency, there's a loss of esteem, there's decreased socialization oppertunities, and none of those are good for anyone, not for the provider, not for the stay at home parent, and not for any future daughters who might see that lifestyle as their role model. but here's a key difference: i grow up in a family much more wealthy then i have being so far on my own, and with a rich boy's mentality, that most people can't afford, and while i am studying so i will be able too, its entirely possible it wont be the case forever.
at this point in time, the solution for this isn't a cultural revolution, its a better economy.