The idea, and I think Rap stars put it best, is to rise up and then buy your Mom a House somewhere nice. Go make it, then bring the rest of the family up. That's why them and NFL / MLB / US sports starts feel like they owe a lot of hungry mouths. It's complicated for sure!
You occasionally see it in immigrant-heavy communities even when they aren't impoverished, because family-locality is a cultural value in many of them.
OTOH, I have seen it, close up, in purchases in ~$200K suburban northern California communities, and in rentals in places in NorCal with similar values, which are much more middle income than impoverished.
It's not really a marketing category, because America prefers the (at least illusion of) the isolated nuclear family as the norm.
OTOH, multiple generations of adults in the same home (or in detached units on the same property) has never been uncommon (and is increasingly common in recent years), and there are certainly homes with features that cater to that use on the market, though unless a particular customer is known to be seeking that particular use the features won't be pitched for that purpose.