That must be the basic mechanism of trading but I do not think it got anything to do against the strategy that we are using should be same or not. If everyone is using a perfect strategy (do not need to be same) then who will lose to give away the money? It means, a perfect strategy today may not remain same tomorrow as well to assure profits everyday. So, there cannot be any perfect strategy with respect to market volatility.

When there cannot be any perfect strategy then how we can assume that everyone will be using same strategy? So, everyone might be following different strategy, it may be same still cannot get us profits in guaranteed way.