If they were never going to be in a serious relationship then they aren’t avoiding the problems of a relationship through hookup culture. They wouldn’t be doing that anyway. I think there’s also always been a certain amount of the population that hooks up because they don’t want a relationship but do want sex. That’s not the same as hookup culture because that’s referring to the pervasiveness of this style of living, and (I would argue) the use of apps and social media to being in more anonymous partners.
I also don’t know to what extent people don’t get into serious relationships due to hook up culture. It’s probably on a case by case basis, there may be some general trends, but based on what I’ve seen people do it between relationships. How long this means very much depends on the person and circumstances, and it probably does space out relationships longer, but it doesn’t necessarily lead to less work in a lifetime. The thing which would do that is setting boundaries in the relationship and not dating men who don’t put in their fair share.
so if they didn’t hook up they wouldn’t be doing labor anyway, they just wouldn’t be having sex.