Another way of looking at that situation is to ask why this cohort of some of the most driven, value-sensitive people in the labor force are so miserable with their leadership that they will voluntarily subject themselves to such a regime for the rest of their life, not for sipping mai tais on the beach but just to implement "...but without that leadership". It is nearly a truism people leave managers (doesn't even have to be direct managers) and not companies.
And if you do not accept that truism, the question still stands, just in a different area. Why are our workplaces so systemically dysfunctional that it gives rise to this behavior in a cohort that arguably should be highly coveted and aggressively retained by their employers?
There are a lot of posts in FI subreddits/forums where people have retired early and are totally lost, asking what they should do to find meaning or enjoyment out of life now that they're not working. They've spent so much of their time and energy of their prime years on working and saving that they haven't had anything left over to discover what sorts of things really bring them fulfillment, and it's incredibly disheartening to see.
The buried lede on those stories is they will not spend out of their FIRE budget on activities to bring that fulfillment, leaving them with somewhat limited choices depending upon their personalities and proclivities (see below), and many have not even planned for how much that will cost.
There are very few personality types that would be happy as a clam spending a hundred years puttering around the stacks of libraries researching a particular scholarly pursuit, then spend another hundred on another specific area, for example. The list of what we do not know is practically infinite, and were I immortal, I could burn a few thousand years researching subjects I find fascinating. Cheap for someone on even lean-FIRE.
There are still quite a few areas of the world that are very sparsely-mapped and their microbiomes sparsely-cataloged to help preserve their bio-diversity. I could spend quite a few centuries just doing that, while hiking and camping. Relatively cheap as pursuits go.
Refurbishing and repairing old artifacts would require some spending on tooling and supplies, but still cheaper than say, learning to fly. I could spend a few thousand years just learning different trades to master craftsman skill levels.
I find the RE experiences others relate that they feel aimless baffling, but only due to my personality. So it is not surprising to me that different personalities cannot conceive satisfaction within the same pursuits. Pursuits that could cost far more than they realized they needed to budget for. FIRE is more about knowing your self than hitting an appropriate total that survives a 2% SWR.
I used to think this way, now I severely disagree, I think nowwhat you want in life cant be anticipated with thought, it can only be hewn out of a rough stone through trial, error, success, and reflection. Atleast thats been my arc over the last 16 years working towards happiness and freedom.
For example, have you ever had a long term regret that you finally faced only to come away thinking, "Now that Im in this position, I should have never regretted not being here." The regret disappears and you feel much more confident in your ability to steer yourself.
You only gain true perspective through actions, not thought, how could you, your thoughts are siloed from reality.
On the FIRE subreddit, anyway, they're very clear that:
1. It's the FI part that really matters. RE is just one possible choice of what to do with it.
2. It's silly to make yourself miserable until you're FI.
3. FI is not magic. It will not meet your expectations unless you've carefully thought through what it is you want to do with that freedom.