There have been lot of talks that index funds are not what they used to :). The reason stock goes high or low is because there is asymmetry in demand and supply

There have been lot of talks that index funds are not what they used to :). The reason stock goes high or low is because there is asymmetry in demand and supply. Previously, some people intelligently bought average stock noticing that average always go up high over long run. However, imagine a world where everyone is always buying average of all stocks. Now there is no longer asymmetry and no longer profits for people who settled for average. So as everyone move towards low cost index funds, they receive diminishing returns.