Today.
Young people being fine with that when they are still in flux is not a new thing. A 21-year-old being nostalgic is almost the basis for a comedy sketch more than a serious concern. I'm not yet convinced they've broken any human patterns when they're still fitting fairly comfortably into the existing patterns on that. If anything I'd bet they're going to discover a larger desire for a foundation than anyone else because the "default" ones have been ripped away and they can't just sort of settle into an existing one easily.