Dating for the 18-21 cohort, outside of the university setting, is already very challenging. Truth be told, some of the women my son has dated in this cohort also live at home.

Very challenging? Most couples have a car between them and a whole lot of appetite for adventure and risque.

Think beyond dating. If they want to get a place together, do they have the combined resources to swing rent?

It's not like everyone lives on a farm anymore. You probably can't just build a starter house on the other side of her dad's back 40 acres.

Rent gets a lot easier when its two earners splitting a one bedroom or even a studio

Sure, but that's true with platonic roommates, too, right?

Usually platonic roommates are less willing to share a one-bedroom, much less a studio.

Multigenerational households are the default in many countries/cultures with many young adults - even high earning ones like doctors, hedge funders, or FAANG SWEs -continuing to live with their parents until marriage. They manage to get in relationships and date just fine. The logistics can be different of course.