thank you for this question!! my answer is: i doubt it, and i don't feel like it's any kind of -pilled, it's just being realistic. of course, there's no one way to define "success" here, but let's say it's "enough women participating in the tenets of 4B, even if not by name, that it is a recognizable movement with an actual impact on marriage and birth rates." and with that definition, i think no. imo, there's 2 reasons that are connected: mainstream american feminism is highly individualistic, and also highly against being inconvenienced.

extreme individualism prevents organizing; they look out for themselves and their future, and also suggesting that women exist as a class with shared interests will get you called out. you can't even suggest that maybe 12 year old girls don't need to be wearing false eyelashes daily without someone coming in about how saying so is anti-feminist because it's femmephobic appearance-shaming or whatever. every time separatism gets brought up in the past, straight feminists have meltdowns about how lesbians just want them to suffer and that suggesting that maybe they stop sleeping with their oppressors is misogynistic. imo american mainstream straight feminists tend to want change without having to do any introspection or work for it.

i'm not an expert on korean feminism, but from what i do know, it seems like there's less backlash/watering down from a mainstream liberal feminism wing than there would be in american feminism, because feminism is already more fringe? obviously many women will push back against it regardless of what country it's in, but like, as far as i know, feminist-leaning korean women who don't personally adhere to 4b still aren't trashing it like straight feminists have done to separatism in the past here.

i do think a lot of heterosexual women might get on with the idea of a "sex strike," without even associating it with any kind of feminist/4b movement themselves, or more seriously insisting on birth control/condoms/vasectomies/etc or no sex. but that's only one part of it. a sex strike isn't as effective if you're still married to them and supporting a man as his girlfriend or wife, raising his children, etc.