You do have the option of going back to work if shit hits the fan. Maybe it'll be harder to find a job, or to find one that pays as well as before, but that's pretty heavily tempered by the fat nest egg you have. It's a pretty big misconception that by "retiring" you're permanently cutting off all abilities to produce income ever again.
It's easy to see "oh if a wealth tax is introduced, you'll run out of money by 50" as if it's a huge hole in the plan, but if you're 30 that gives you 20 years of draw down time. A change in the market or legislation won't sneak up on you and suddenly drain you of all your cash - if it does, it's probably something affecting the entire population. You'll likely have a year or two of drawing down more cash than you should before you pivot your plans.
The most vulnerable time during FIRE is the first few years of early retirement (where a market crash could wreck you), but is simultaneously the point where you're still at your most employable (plenty of relevant contacts, skills that aren't out of date, and a relatively small gap on your resume).
As browsing any discussion on recruiting and interviewing with illustrate, hiring is already fucked up, and adding age plus a multi year gap would make getting a new job quite hard, let alone one that matches the compensation one has today.
Sure, landing the same tech job may not be feasible. As I mentioned, the big nest egg should ease that blow. You can instead get a lower paying tech job you're plenty qualified for. You can also get a job doing something unrelated to tech, like Uber/gig work, secretary, waiter, creating on Etsy, or really anything. A disruption to early retirement isn't going to be so dramatic that you need to get your same 6 figure income as before in order to stay afloat. It's something where an extra $15k a year coupled with some cost cutting will get you through a recession with minimal damages (cost of living dependent of course, but I'm assuming a conservative ~$60k/yr expenses). Landing something more lucrative creates a noticeable surplus.
This is a risk I think that people don't give enough consideration.
I know a guy who FIREd a while ago, long before we called it FIRE, and he's had a heck of a time landing another corporate job. He had a very successful business development firm and took a buyout from partners so he could move away from NYC and spend time with his kids. His kids are all grown up now and he's been looking for jobs and...crickets.
If you stayed active in relevant circles, perhaps doable given personal contacts.
But I agree in general. If someone retires at 40 and realizes 5-10 years later this isn't working out, that's a pretty big uphill climb for conventional professional employment.
It's easy to see "oh if a wealth tax is introduced, you'll run out of money by 50" as if it's a huge hole in the plan, but if you're 30 that gives you 20 years of draw down time. A change in the market or legislation won't sneak up on you and suddenly drain you of all your cash - if it does, it's probably something affecting the entire population. You'll likely have a year or two of drawing down more cash than you should before you pivot your plans.
The most vulnerable time during FIRE is the first few years of early retirement (where a market crash could wreck you), but is simultaneously the point where you're still at your most employable (plenty of relevant contacts, skills that aren't out of date, and a relatively small gap on your resume).