If you had an unlucky year and had to spend an extra $10K on various things (car breaks down, medical expenses, moving for a job) it's probably not a big deal for you. If a leanFIRE person had an unexpected extra $10K expense, they'd have to cut $10K out of the rest of their budget for the entire year.
If you're already squeezing by on $30K/year like this author, somewhere between 1/2 and 2/3 of that might go to basic living expenses (rent, utilities, food). If the other 1/3 of your budget gets wiped out by an unexpected $10K expense, it's going to be a very lean year.
This is the problem with most leanFIRE plans: They only work if nothing ever goes wrong, no unexpected expenses occur (for 4 or more decades straight), and a person's lifestyle never expands at all.
The notable exception is called a "sequence of returns risk" (SORR) where either something bad happens in the first few years draining a really large portion of your original savings (more than $10k) and/or the market undergoes a recession during the first few years, and if you withdrew the full 4% from your investments while their value was markedly depressed, you would never recover (without additional income). In my opinion, a proper retirement strategy should account for SORR; some padding (i.e. the wants portion of your budget you can reduce during a lean year), reverse-glide strategy where you can draw from cash/bonds instead of equities in case of depressed value equities, etc. In many cases, this scenario happens so early in retirement that anyone retiring at a younger age has relatively good prospects of rejoining the work force to get to the other side, and then will likely be very well prepared for a second retirement with a decreased likelihood of yet another bad sequence of returns occurring before their nest egg has grown well beyond 25 times annual expenses.
And all retirement plans should be flexible - some years where you might spend a bit less than the target, but have room to change that, particularly if your invested assets grow beyond the original necessary funds.
I don't think that's the case if you're retiring early. The 4% withdrawal rate was based on a 30 year retirement. You need to go a bit lower if you want to have minimal risk of running out of money for a much longer horizon.
You're more likely to die than run out of money!
That's a much higher level of risk than I would accept.
Were you reading FIRE blogs or extreme frugality blogs? Or maybe I can just ask "how do you define extreme frugality?" (I think of myself as kind of frugal, and planning to have the choice to avoid compulsory paid work before I'm 50, but I also live in one of the most expensive areas of the United States outside of big cities / California, with somewhat regular trips to Disney World and other countries.) But a blog like earlyretirementextreme.com isn't focused on high earners cutting down on consumption and retiring early (that's MrMoneyMustache.com) - it's a version of extreme frugality and self-reliance (and adaptability regardless of changing life circumstances.)
> bare minimum savings
I assume by this you mean "leanFIRE" as in "just enough of a nest egg to retire with 25x your annual expenses and everything goes perfectly?!" Of course, that sounds like a recipe for disaster, and I think in some cases it's a bit of a "oh I can quit my stupid job at the exact moment I hit this magic number" mentality, but a misunderstanding of putting a real plan in place for a future that is filled with variables. Depending on the blogs you frequented, they could be "copycat" blogs that just took the juicy headlines from more in-depth blogs and throwing up quick articles so they can get some ad revenue.
Any idea, handled poorly, is going to either come off unappealing or be riddled with shortcomings. That doesn't mean the original idea can't work (and it does for some - some by luck, others by proper strategy.)