When I got my economic victory (under 60 turns or so), I was surprised that the world bank costs were so low, despite being in 2 wars and having hostile relations with 3 other AI. I had thought it would take 1000s of gold and 100s of influence, but seems to be like 10% of that. Perhaps because in had a lot of economic legacy points from earlier eras? If so, I think the effect is too strong, especially since the access to resources that earns legacy points in earlier eras already makes it faster to get 500 factory points.