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.