@NoraLenderbee, you are picking at one part of the portfolio (gold) during an unprecedented period of western prosperity which has been fuelled by cheap energy and debt expansion. All parts of the portfolio cannot be winners at the same time. That is the reason it works. You then go on to imply that strategy is flawed on the basis of one component. Did you even bother to look into it in more detail before you shunned it in favour of your own ideology? Your returns are safe now matter what happens.
It doesn't matter what withdrawal rate you choose, 4% is based on returns was safe in the good old days of cheap energy and debt expansion, but those were both one way tickets to the good times. In period of economic distress or even just a bit of stagnation, in order to retire you'll need a safer withdrawal rate whichever strategy you follow, 3%, 2% or even 1%, regardless your capital is still safer with the PP in the long run.
I appreciate I haven't quite distilled the intricacies of the strategy down into a handy bite sized paragraph, further reading on your part is required. Hence the link to the book, it does a better job at explaining why it works in all economic climates better than I can.
Yes, the strategy assumes that society isn't about to be up-heaved and the west will not succumb to socialism, communism, technocrat-ism, authoritarianism or any other political model that aims to seize your assets. Though it will do a good job of weathering any storms capitalism throws at us.
It's a low risk portfolio compared with a 100% equities, or say 60% stocks and 40% bonds index funds and the reason I shared it is that OP's SO might feel more comfortable knowing that their capital is less exposed to volatile markets and safer than purely index funds or RE strategies in the long run.
This chart below speaks for itself, play close attention to the periods of bubble bursting 2002, 2008: