I don't know why I care enough to really look into this, but just for the record, early predictions for Black Panther were in the $100m to $120m range. It ended up closer to $200m.
http://collider.com/black-panther-bo...d-predictions/
So in summary, I don't know why anyone cares about predictions since they seem to be a ballpark estimate that is often wrong on huge scale.