Past performance is not indicative of future returns. Do you know anyone still running a risk parity 60% UPRO/40% TMF (3x long S&P 500, 3x long 20-year Treasury Bonds) portfolio? That portfolio composition had massive returns, until the Fed started hiking rates.
The annual implied volatility of SPX is around 15-20%, if you want to withdraw 6.5% a year at 40 and have to restart your career at 55, be my guest.
A 40% drawdown on 600k is -240k which puts you at 360k, 6.5% of which is $23,400. Starts getting pretty tight if you need to sell assets for cash which reduces your future returns.
Most of the reasonable FIRE advice (e.g. https://earlyretirementnow.com/ quality) suggests a ~3-3.5% withdrawal rate, which has been measured using historical data way before the current secular market.
Is your take that even such withdrawal rate wouldn't work anymore, moving forward?