Whichever kid has the most when they die wins.
But yeah, there are way more dimensions along which to measure success. Almost every one is more important, in my view, than how much money you have when you die.
What about preventing the study and discussion to be myopic or monocultural?
What about a study with several cultures ranked by country? The successful criteria could be measured by how the status ladder is composed in each country and making the cultural cosmovision of each country explicitly defined.
It would reveal a lot.