Is it accurate to say that the difference between index and non-index funds is that a) index funds don't trade as much and b) index funds publish their componen

Is it accurate to say that the difference between index and non-index funds is that a) index funds don't trade as much and b) index funds publish their components? Is there any reason an "active" manager cannot behave like a passive manager? Is index investing just outsourcing the stock picking?