Not an expert but seeing the quick rise in popularity in anything makes me nervous. eg. Index funds and ETFs. When Apple is the Number 1 holding of all index

Not an expert but seeing the quick rise in popularity in anything makes me nervous. eg. Index funds and ETFs. When Apple is the Number 1 holding of all index funds, and investors are blindly driving up aapl stock becuase they continue to want 'index' funds.. how do we protect ourselves and our economy from a major reset/correction?