I try to imagine what it would be like to be on one of those FIRECalc lines that is descending through the true starting value and keeps going down for decades. Sure, in the past US history many of them have rebounded, but when you are actually riding the line in real time there's no telling what will happen, the slope of the descent could easily increase as you zoom toward the X-axis.
So, while a 1% real return and 45 WR would last for 30 years, without knowing the line's slope in advance and when the grim reaper will be visiting, worry would significantly degrade my QOL starting at about year 10.