Tradition being up to the present, actually, in large parts of the world. (Repeating a comment to another article:) I suspect that people living with family until 20s/30s is likely to be much more common than people here expect, and that not doing so is an anomaly of the current age occurring in only certain cultures, with a possible return to norm in the future.
If you're discussing "protestant work ethic"-based communities, and "multigenerational housing"-based communities, they are generally mutually exclusive.
I suppose it depends on whether by "Protestant work ethic", you are referring to people who are actually in the Protestant/Calvinist faith, or if you are using it as a euphemism for general workaholism, as there are many non-Protestant communities which espouse hard work and frugality as main tenets to follow in life, which do have a higher rate of multigenerational-housing-based communities.
Also, it would be interesting to explore exactly how and why "protestant work ethic"-based communities and "multigenerational housing"-based communities became generally mutually exclusive, whether there is causation, or just a happenstance correlation.
