There is no such thing as passive investing. Index funds are market cap weighted and thus follow the momentum factor (this has dominated markets for the last 10 years) which is why index funds have done well.
When things turn, active management will succeed because different factors will become dominant. Ultimately the market is about price discovery, and active managers do this.
Active managers are willing to provide liquidity to the market at a particular price level that matches their valuation, this is how price is discovered.
Passive investing adds or removes liquidity based on flows, or the decision to invest - with no care about price. THe moment sentiment shifts and the decision is to not invest, then a big sell off will occur, then active managers will jump in at a suitably depressed level.
