You don’t see equal weight outperformance because the last ten years is the S&P500 cap weighted / growth bubble. You don’t see a bubble when you’re in a bubble.
RSP started 5/1/2003, and since then it has consistently beaten SPY literally until the AI mania talk started in earnest in 2024.
RSP,SPY | PerfCharts | Free Charts | StockCharts.com
Since the AI narrative has come under question in the past few months, RSP has been beating SPY again, though both are down since 12/31/2024.