The idea that there is some perfect WR that can lead to 100% safety is I suppose at a level of understanding of say a 3 out of 10.
There is a massive amount of complexity in this issue and indeed in the whole picture of FIRE.
I think people should read this post. Admittedly it's from another forum but it's really good.
https://forum.mrmoneymustache.com/post- ... msg3061789
Some random points:-
This is the thing about FI, it's an arbitrary number you make up for yourself.
The trick is to view the data as a guideline and your decision making based on that data-set is dependent on your specific circumstances and there are also opportunity costs.The person has set a largely arbitrary savings goal for themselves, met it, and chosen to leave a job that they no longer feel financially obliged to continue working.
Everyone would prefer a lower WR but you can cheat yourself by having really low expenses. This potentially can consign you to a life of misery. Your mates want to go out for a beer and you have to say no. You can't go on a date because you can't afford it. You can't see your kids because the petrol costs too much to go and see them and public transport isn't an option.
You can get to a really low WR and consider yourself safe but have worked for years in a job that you don't enjoy.
There are other factors as well such as other assets or benefits outside of your financial assets. There is also your age and health to consider.
It all comes down to looking at the data and making the best decision for you and not stating well a WR of 4% is inherently flawed and will not work ever again. It's ludicrous to state this without looking at your specific situation. I also wonder what the pay off is for stating this point. It's meaningless and it can't be proven.