I can't help but think a lot of people haven't actually read Big ERN's posts. The entire point of his posts is there is nothing "modest" about the flexibility (whether going back to work or cutting back on spending) required to avoid portfolio failures and portfolio failure (or the flexibility required to avoid it) is a much, much, much worse result for many people than simply working until they have a lower initial withdrawal rate.
another way to say it is this: people who talk flexibility have mostly never quantitatively analyzed what that actually means, nor have they considered that you lack information at the time flexibility decisions need to be made - going back to work, cutting costs, depleting a cash cushion, etc. are all decisions one has to make without knowing what the future holds.
ERN makes a very strong quantitative case that an extra two or three years of work, especially since each of those years will typically be at your earning peak as you generally make more annually per year until your 50s - to get to a lower and safer retirement rate is the right move. The main argument against it is that people don't want to work another few years.
It's especially weird IMHO given how much uncertainty there is about economic growth and healthcare expenses going forward; nothing even remotely like the current situation is really to be found in the historical data so short of simulations (as opposed to backtesting) with some reasonable parameters confidence should be low.
While not necessarily advocating a higher WR, I thought it worth stating the obvious that one might also consider that having more available disposable income is an additional 'upside' of working a few extra years.
This is a factor that each individual might consider in their plans.
I think he is assuming that people reading his work are first world types, who have work that is reasonably enjoyable, and where the money is relatively good. Hence the conclusion to advocate a plan where people might choose to work a few extra years.
With a little extra cushion one is both prepared for an unexpected medical issue and has more flexibility to splurge on a once and a lifetime travel or hobby opportunities, that might be expensive. If ones priority is to see the world and spending extra money brings no joy, then go for 6%+, as that fulfills your life dream.
Its all individual choices, as has been often discussed.