This is a very informative analysis using the SPX/DJI ratio. In recent decades this has helped at identifying recession and expansion cycles. As this chart shows on the 1M time-frame, after each crash since 2000 and the Dot Com crash (Housing crash, China slowdown, Brexit, Oil Crsis, Trade War crash and the more recent Inflation Crisis), the ratio started to rise, meaning that the S&P500 started to outperform the heavily industrialized Dow Jones Index, which led to a new Bull Cycle.
Since the bottom of the Dot Com Crash, the ration has been trading within a 20 year Channel Up, which is limited by a Lower Highs trend-line. If broken we can start talking above a new mega expansion phase.
The 1M MACD just completed a Bullish Cross last month, suggesting that the current Bull Cycle may only be at its very beginning. Regardless of all that, we believe this is a very interesting ratio to follow and that has offered useful conclusions to you. We hope you enjoyed it!