It seems like you’re saying that the practical weakness of forecasters vs experts is their inability to make numerouscausal forecasts. Personally, I think the causal issue is the main issue, whereas you think it is that the predictions are so numerous. But they are not always numerous—sometimes you can affect big changes by intervening at a few pivot points, such as at elections. And the idea that you can avoid dealing with causal interventions by conditioning on every parent is usually not practical, because conditioning on every parent/confounder means that you have to make too many predictions, whereas you can just run one RCT.
It seems like you’re saying that the practical weakness of forecasters vs experts is their inability to make numerous causal forecasts. Personally, I think the causal issue is the main issue, whereas you think it is that the predictions are so numerous. But they are not always numerous—sometimes you can affect big changes by intervening at a few pivot points, such as at elections. And the idea that you can avoid dealing with causal interventions by conditioning on every parent is usually not practical, because conditioning on every parent/confounder means that you have to make too many predictions, whereas you can just run one RCT.