<i.Well according to intercst, the safe withdrawal rate is 4% and you would need 25x your FIRE budget to retire. Other than a rather large question as to whether that is remotely accurate long term (a diversified portfolio of US stocks, real estate and international/emerging market stocks is unlikely to deliver the same results in the past and so the withdrawal rate figure is wrong. 2%-2.5% is much more likely making the FIRE multiple 40-50x FIRE budget and not 25x),

Perhaps you would care to explain exactly why are you so confident that long-term results of the stock market in the future will be only about half the level of the worst 30-year period in the past 100+ years?

Or, to put it in perspective, why we will be looking at the Great Depression and the stagflation 70s as high-growth periods?

Intercst never advertised the 4% rate as "accurate long term". He advertised it as giving a high confidence of being able to continue through the worst 30-year period in the history he could accumulate. Naturally this implies that if future returns are a bit better than the historical worst, you'll end the 30-year period with a spot of change in your pocket - if future returns match the historical average, you'll be filthy rich. But his concern was for the worst one could reasonably expect.