S&P 500 - Why try to beat it?

Wouldn’t that be enough for most people should they just stick with a fund that follows just the S&P 500? Might not be as well diversified and wouldn’t have international exposure compared to Total US stock market, but it still is able to produce a 10% average return. And would think it’ll be able to retain the average for the long run with their strong holdings.

I personally invest in FSKAX and FTIHX (70/30 asset allocation), but thought it was just an interesting observation when you see and hear others invest in a slew of questionable funds trying to outperform the S&P 500 when they can just invest into a simple S&P 500 fund and call it a day.

Thought?