I am not aware of “a lot of studies” that show a CAPE ratio can actually be used as a crystal ball for anything useful with respect to the 4% rule (or really predicting much of anything prospectively).
In fact, it has not worked at all since it became “the next greatest thing” around 2011 and everyone writing those articles then said it meant we were about to have a lost decade.
Remember that lost decade in the 20-teens? Yeah, me neither.
It didn’t work. At all.
The problem is that it is not a stable mean to revert to and is much higher on average in the post-internet world than it was in the last century.
So, if it “works” as a crystal ball in the future, it will be due to random chance and not via any magical predictive powers.
“Not spending much money” always works, though. But you don’t need a crystal ball to apply that strategy.
BTW, this is not a “high rate, high cash return” environment.
It is a very average one by historical standards, just higher than the extremely low one after the GFC.
As Bengen found in the original 1994 SWR study and everyone has found since, holding more that 10% of cash or t-bills in a portfolio tends to degrade the safe withdrawal rate.
Nobody has ever contradicted that finding with any historical analysis.
