Because markets are actually making a LOT of different decisions with incredible granularity and specificity across time and many other metrics. This is essent

Because markets are actually making a LOT of different decisions with incredible granularity and specificity across time and many other metrics. This is essentially computationally infeasible to do in a centralized way even if you make many simplifying assumptions. It can go wrong of course! But there essentially is no alternative that is even close to working.