I'm not sure that intelligence, beyond a certain baseline, really enters into the formula for creating long lived social structures. For the individual, there is no tangible benefit to creating structures that will last more than a few generations. After a few generations, as you point out, they will require the efforts of other people to keep alive, so there is little that the originator can do to ensure that the structure survives.
The most rational course of action for all individuals involved in a society is to maximize their personal benefit and plan to pass that benefit on to their offspring. Tangling with those who are successful at maximizing their benefit has real negative consequences, so the most rational action for the downtrodden is to take as much of the scraps as possible or jealously guard what you have while staying out of the eye of others.
The ambition to create structures that will outlast you and your offspring comes from irrational motivations. Historical drivers for this are abstract concepts like duty, fairness, or religion. There is no tangible benefit to creating these structures and there is often great personal cost. As there is no assurance that the structures will even survive, no matter how well you craft them, it's hard to say that building them is an intelligent choice.
I think that improving the lot of humanity as a whole is a noble goal, but I don't think that it has anything to do with intelligence or rationality. History is littered with people who have tried, and sometimes succeeded, to do so at great personal cost. Often their success only lasted a few generations, if that, before being undone by others. What real benefit to we get from creating these structures and how does that benefit weigh against the costs required to build them?