The 4% rule failed after the great depression, and when enough history plays out, it might also fail during some of the severe downturns of the 2000's.
The bolded statement is not true, and Sol and others have already debunked similar statements that you made in the 4% rule thread. Go run cFiresim at either a 60/40 or 75/25 stock/bond allocation, and you will see that the only failures occurred for start years in the mid and late 1960's, due to the 1970s stagflation era. The Great Depression did NOT cause a failure of the 4% rule. And if you run a 17-year sim that captures the Y2k retiree, he/she is doing demonstrably better than any of the 1960s/70s failure trajectories were doing 17 years in. I'm pretty sure this has been pointed out to you before also.
Please stop spreading misinformation.
All you have to do is look at Table 3 in the original Trinity Study and you'll see that for a 30-yr time frame with an adjustment for inflation between 1926-1995 the success rate was only 95%-98% for a portfolio that had at least 1/2 stocks, 71% success for 25% stocks, and only 20% success for 100% bonds. Not sure why my statement is true! Let's see what we think about you not worrying about the year-2000 retiree...
cFiresim is only one simulation tool, and it doesn't even agree with the results of the Trinity study. As long as people are going to quote the 4% rule I'm going to stick with one of the sources of that very rule. But let's use it to simulate a 30-yr outcome starting at 2000. We don't need to stop at 17 years of simulation, we can do it in two stages to try and add on the other 13 years to get a proper 30-yr time frame, shall we?
I used the cFiresim default calculations with a 2017 retirement date and a 2034 retirement end year. Someone starting with $1M in 2000 would only have about $629K of their portfolio left in a US market - with a lofty CAPE ratio of 30 - we can't even factor in how expensive the market is, but that doesn't sound very safe at all.
Put that $629K back in the simulator and run it for another 13 years. Adjusting expenses for inflation, $40,000 in 2000 is now $57,545 in 2017, so that's our starting expense number, and the simulations years are 2017-2030. Now let's count how many times the portfolio fails over the 134 historical simulations. The answer is 48! That's the best way I can think to simulate a 30-yr horizon starting with 2000, and I get a 36% failure rate with this method. If we assume that market returns will not be as good for the next 30 years (CAPE research shows this to be very likely) then you would probably get a significantly higher success rate.
Please stop spreading misinformation.