this is a good point on efficiency of the market, however it is not correct conclusion that you cannot find companies in that market that are not better perfor

this is a good point on efficiency of the market, however it is not correct conclusion that you cannot find companies in that market that are not better performers than others - obviously there are companies in S&P500 or any other index that perform better than others for any given period of time. But if you focus on particular set of companies (tech for example) your risk increases since your diversification decreases. Given your own example, obviously AAPL outperformed market for the past decade. Whether someone could have predicted that is a different question though.