I suspect another element is people not giving up on relationships but giving up on and/or delaying commitment/marriage/having children.
If your employer is pressurising you to work long hours, not take holidays or sick days, you can't afford to buy a flat/house and childcare is expensive the traditional get married, buy a house, start a family route that previous generations went down doesn't look very viable.
Well yeah that's part of it, and also there's how in recent times we've seen the disappearance of a lot of what are known as "third places", social gathering spots away from your home or your work (think like, a park, or a library, or a community center, or a church, or anywhere you could just go to hang out and meet people)- or at least, we don't have very many places like that where you can socially gather without spending money, and depending on your age and race, hanging out in a place that is free like a park might get you negative attention from the cops. And that's not even getting into how a lot of our infrastructure is really unfriendly to anyone who doesn't have a car.
TL;DR version: We've made it so it's a lot harder to meet new people IRL and we've made it so nobody really has time or money for anything after work, so unsurprisingly lots of people just say "screw it, I'm binge-watching Netflix and playing Civilization all weekend" because that's all they have the energy to do.