real, but I think a lot of people posing that argument are also trying to speak to the fact that what you’re describing—friends deprioritizing you once they have a romantic partner, i.e. amatonormativity—is itself a problem. that people Need to unlearn that tendency so friendships can be more fulfilling on average
So here’s the question, if it’s so common isn’t that the standard and we are the weird ones? I’m from small college town nowhereville where marriage is more important than the degree so literally everyone but me and my other roommate don’t have relationships and the people that do will never have lives outside of their partner
amatonormativity is definitely the standard in the US, but at the risk of sounding smug or conceited, I think it’s pretty common for critical thinking and strong ethical principles to lead to opinions that run counter to the standard. cause for instance there were points in history where people would laugh at you for questioning slavery or saying women should be able to vote
I don’t have a ton of specific insight into Why things are like this here but I know that like you said, the emphasis on marriage is a huge piece of the puzzle. something to do with patriarchy, the way the institution of marriage was originally about keeping women captive as little more than property. things have changed but the legacy remains