25 years married, so pardon my knowledge of modern dating being what I've heard on social media (which is always from people complaining about it, of either gender) as I'm not on any!
As I understand it, for a lot of young men, one of their preferences for settling down is that their partner's list of ex-partners is not longer than their own. (If so, there's is no point debating the gender-political rights or wrongs of their preferences because you're not going to be able to argue someone into falling in love or wanting to marry someone.) On swipe-dating apps, that creates an incentive for neither party to settle down. One party is so successful that the app keeps signalling they should keep their options open (here's more matches, why settle for this one). The other finds that matches pass their visible preferences for dating but not their invisible preferences for settling down with (because not being too successful at the dating game was one of their hidden preferences). The vitality of the market for dating kills the market for marriage.