No one makes compromises unless they have to, and unless you have a big soundproof house, two or more couples living together are going to bump into each other.
I see older parents moving back in with kids due to declining health, but otherwise the consensus seems to be that having grandparents nearby in a separate home is ideal.
However, children of immigrants are especially keen to assimilate into the receiving culture, so much so that they often go beyond what natives do. For immigrants and their children, a clash of cultural values may be a larger driving factor than what's the natural for people in general.
The above might not apply if you have a large enough space with sufficient sound proofing and multiple kitchens, but that's not the reality for most people. There are positives, but my observations suggest that the biggest factor in determining if you live in an intergenerational household is whether or not children and the parents can both afford to live in different houses.