Why is S&P 500 investing the default when the Nasdaq Composite has performed better over every 30 year window?

A little Google Finance magic and you can create some plots showing you the "multiples" of your money had it been invested for X number of years (I prefer this over unwieldy percentages).

If you invested your money into one index for 30 years that first dollar will have grown by the multiple below. I show two periods the last 30 years, and the 30 years before that:

Period #1 (1995-2025): S&P 500 - 7.6x | Dow Jones - 10.1x | **Nasdaq - 21.7x** ([plot](https://docs.google.com/spreadsheets/d/e/2PACX-1vRgRe1DDKrRvQFzPZaBTs4kUKH2D1k8EPflAY7JsAcBi2635-891Q3PSTL_eMIaVXK-CMGH2c6TP2tw/pubchart?oid=97885568&format=interactive))

Period #2 (1965-1995): S&P - 5.7x | Dow Jones - 4.6x | **Nasdaq - 8.1x** (plot: [plot](https://docs.google.com/spreadsheets/d/e/2PACX-1vRgRe1DDKrRvQFzPZaBTs4kUKH2D1k8EPflAY7JsAcBi2635-891Q3PSTL_eMIaVXK-CMGH2c6TP2tw/pubchart?oid=1857506659&format=interactive))

Nasdaq does better. Why are we generally piling into VOO or SPY instead of QQQ or ONEQ?

(I also understand that it doesn't make sense to factor invest into a market exchange, of all things, but what about it makes it more performant over our one true love S&P 500?)