You have to define success. The 4% rule is successful if at the end of 30 yrs you have even ONE dollar left.
I don't define "success" as having a buck to my name.
At 5%, the chances of having zero dollars increase. But remember that these are odds. If you fail, you fail BIG. You run out of money. These rules don't really have anything to do with maintaing capital.
Simply put, the study showed that for each of the prior 25 years, if you started withdrawing 4% and maintained that same dollar amount, you would have at least a buck after 30 yrs in all but 2 of those start years. This says nothing about the future or preserving capital. Unfortunately if you are a person who started in any of those 2 start years, you were SOL, with NOTHING left.