No decision-making system is going to guarantee corporate success. The strategic decisions that corporations have to make are of mind-numbing complexity. But we know that the more power you give a single individual in the face of complexity and uncertainty, the more likely it is that bad decisions will get made.
Groups are only smart when there is a balance between the information that everyone in the group shares and the information that each of the members of the group holds privately. It's the combination of all those pieces of independent information, some of them right, some of the wrong, that keeps the group wise.