I'll address each of your points in turn, as best I can:
I really wonder sometimes if all these folk heading for RE at the rate of knots realise that at a certain point there's really no choice. You'd be VERY lucky to exit the workforce at 45 and go back in at 55 if you needed to. Especially if you're in a technical role.
If you read the different blogs that folks have posted, you'll find that quite a few folks are quite aware of this issue. Naturally, it depends on what one's career actually is, doesn't it? Some careers are very easy to step back into, others are nearly impossible. I've noticed that those folks who can't easily go back to work in their field at near their old pay tend to build a bit more safety margin into their plans.
Yes, I know the whole point is that you have enough of a pile that you don't ever need to. BUT. No one knows what's going to happen.
Exactly. The more miles you drive, the more likely you are to be killed or maimed in a car accident. If you drive to work every day, particularly a long commute, you might die young. So, you do what you can to maximize the likelihood that things will go well and you minimize the risks of bad things happening.
So, the only thing that you're trading off is more income against more freedom. The breaks could go either way, but being happy, having time and energy to eat healthy and work out, and driving less ups your odds of good results. Those things are all harder to do with a full time job.
What if you financial backstop becomes worthless overnight? What if inflation goes through the roof and suddenly a loaf of bread is $500? What if you get multiple personal disasters at once instead of the one or two you've allowed for?
Well, a lot of us diversify. For example, we have farm income from farmland we rent out in one state, rental homes in a 2nd state, social security, stock income, and hobbies that can be turned into money-making ventures.
The stock itself is diversified - the index funds we use own bits of thousands of companies around the world.
We'll have the time to garden to raise food, years to learn new skills and time to make more contacts in our city. People will need a place to rent and rents tend to go up when lots of people are losing their houses.
Plus, a whole lot of us have two different numbers we use to plan our FI - the minimum we need to get by on and the amount we plan to get by on. So, if things go bad for some years, we can cut back and still be ok. If you only need to earn $10,000 to make ends meet for the year, you don't have to get a great job, pretty much any one will do.
Would it not be far more sensible to keep your primary income stream alive for as long as possible?
When we pull the plug next May and quit our jobs we'll actually be getting a raise.
Huh?!
We save a huge percentage of our salary and invest it. When we retire we won't have to do that any more and our planned retirement income is actually larger than the amount we're living on now. :)
My personal take on RE is NOT stopping working at all, but shifting into a role that I find fun. I plan to keep the dollars rolling in for as long as I'm entertained, and then find something else that keeps new money coming in. Have I missed the point???
There's no reason not to accept money for doing something you want to be doing anyway. That's what we'll be doing. I enjoy fixing up a house. The work is interesting and fun - just not so much fun when I've got a full time job at the same time.
I also enjoy making art and plan to sell it. But I'll have the benefit of being able to do most things the way I damn well please instead of pandering to the lowest common denominator in taste in the hopes of making a sale.