Nasdaq ETF vs S&P500 ETF

I've always heard people on this sub suggesting to invest in S&P500 ETF such as $Vanguard S&P 500 ETF (VOO.US)$ , $SPDR S&P 500 ETF (SPY.US)$ .

But given how the market is going for large companies (tech and non-tech), why don't more people invest in Nasdaq 100 ETFs?

I do understand that buying SPY has less risk, more diversification into more sectors, and you're getting a broader overview of the US market, but buying Nasdaq 100 would have significantly outperformed the S&P in the last 5-10 years.

Any thoughts?