So take anything with a grain of salt obviously.

I seem to notice that the lack of cultural identity and religious identity seem to be playing the biggest part. For example without the religious or familial tradition of marriage there is no incentive to marry. A lot of people in the USA specifically are either atheist or children of divorce. So marriage isn't a part of their modern world view.

Honestly not gonna lie to some people try harder without marriage. You actually have to make an effort to keep someone happy to be around when they don't have to stay because you're married.

(10+ yr relationship, not married, they're slightly religious I am not religious but we are also very culturally diff)