I retired in 2017 and never spent 1 minute thinking about inflation. When i worked i never spent a minute thinking about the “required” size of my retirement portfolio. Finally, i believe less in an “average rate of return” than i do in the trinity or 10 commandments—and I’m an atheist.
I simply live below my means as I always have and trust that if things get so bad in investing that a 60-40 portfolio doesn't keep pace with inflation over the long term that politicians will be under intense pressure to fix it and will do so.
The rest is noise and silly talk. And life is more about living as frugally as you can, so you can save as fast as you can, so you can retire as early as you can, and then spend as much as you can.