Investing in S&P500 is a strategy, which can be optimised. You can ask if it is better to invest in top 100 or top 1000 instead of a top 500 index. Why even go after the top index? There are all sorts of inactive strategies available.

So in a sense, the "active" manager is just as much a monkey throwing darts as the "inactive", yet one of them is better than the other.

Why can't a third monkey be even better?