If anything, I would argue that the family utilizes economical mutual-aid, that is above mere distinctions of socialism or capitalism, since the self-interest of ensuring our biological relatives survive is it’s own reward (i.e. helping my siblings to survive ensures that I will have more biological relatives, & also increases my chances of receiving aid when I may need it).
To put it more succinctly, it could be described as an honor system that works, since there is a significant genetic pre-disposition (that is also socially & economically reinforced) in family members honoring the ability to receive & give mutual-aid.
I think it would be much harder for such to exist with non-genetically related individuals, unless of course, we are all tricked into thinking we are one big family via the collectivist doctrine of state-society, which, despite families largely being unconditional, require even more unconditional obedience (i.e. voting, coercion, war, taxation etc.) in order to sustain itself.
I think any serious proponent of the state-society realizes this, & it frankly scares the crap out of them; the possibility of individuals & crimes being accountable. The possibility of life being a harder for those who do not wish to work hard. It’s in this that is no surprise that despite living in state-society, families largely regard parasitism as an offense, even as one generation after another has a majority that unconsciouly accept parasitism as a valid doctrine.