Communication, as soon as people are allowed to exchange information, results get a lot better. Teams can start planning, based on real customer demand,backlogs and so on. This changes everything.
which makes perfect sense because among the assumptions of free market economics which are required to make the invisible hand do its work is "perfect information": buyers and sellers share perfect information about conditions, costs, markets, supply, demand, etc.
and still there will be bullwhips because the future contains uncertainties like "when is the next coronavirus outbreak?"
Silicon Valley operates on secrets (what do Google Amazon and Facebook do with your data? anything that is not simply further stacking the deck against you?) the elimination of which is the direction reform minded people should go with regulations.