We could imagine, for example, a United States that became and remained very poor after having all its natural wealth siphoned off by European firms under predatory terms during the Great Depression. It's hard to tell if the world would've been a better or worse place (maybe the profits would've been reinvested into stabilizing Germany's internal politics), but certainly US citizens would be much worse off today.
On the other hand, could a World Bank have saved Germany from Nazism and ended the world wars after episode I? Probably. Who really knows.