They then would move out to a bigger more expensive city and feel more financially comfortable than they would have. This was in first generation immigrant families, which as the article notes, is where this practice is more common.

Even if they do, it still means they failed to save up that money without having to live with their parents.

This is just the WSJ-reading "haves" justifying the increasing stratification of society by reframing a clear regression[0] as a "responsible individual choice" which that crowd LOVES.

(EDIT: it's also cope for the parents of those kids for the not-quite-THAT-elite WSJ reader crowd who doesn't want to believe either their kids are failing or their economy is faltering.)

[0] Even if you see the everyone-moves-out vs multigenerational-housing trend as a negative overall, the broadening loss of the ability to make that choice is a clear symptom of overall economic weakening.

Most people in my circle who bought a home in California before the age of 30 did exactly this.

So what changed?