This analysis appears to have been done while only looking at prices. Since a very material portion of equity returns over time comes from dividends, if you don

This analysis appears to have been done while only looking at prices. Since a very material portion of equity returns over time comes from dividends, if you don't count reinvested dividends over such a long period you are going to end up dramatically undercounting equity returns. TL;DR; gold didn't beat the S&P 500 over the past 15 years.