At a certain point, active strategies that attempted to avoid the bad and only pick the good assets would become effective again. I suspect we'll learn during the next crash that this has become the case, that some companies really are more productive than others, and that indexing simply results in an everything bubble. S&P 500 seems like a particularly arbitrary example, because it's an actively managed list of companies. Any time you have consensus, it's safe to assume that the pendulum has swung too far.