The OP means in the top 0.1% among PhD students in your field.
If you want to get a tenure-track position in a good department, then in many fields, you do have to be that good. (0.1% might be a bit of an exaggeration, but not that much.)
More generally, you should be aware that your post is very specific to the field you worked in. Computer science has a very well established PhD -> industry pipeline, and lots of money to throw at grad students. There are many disciplines where doing a PhD is a very different story.
That's the problem. The housing market isn't literally insane in the whole country.
Can I afford to live in the Bay Area? Also no.
Where in the UK? What field? There are several important details you are leaving out.
I remember seeing colleagues from the UK who got a good stipend. I think in general in the UK doing a PHD was good at that time, specially because it usually lasts only 3 years.
Nevertheless, after spending other 4 years in academia, I turned to Industry and would never go back. Academia is broken at this point in time.
Oh come on. I'm doing a PhD right now, but it's simply unrealistic to ask everyone admitted to the program to delude themselves into thinking they're in the top 0.1% of those admitted to the program.
> You live off a meager stipend for about a decade
I paid a mortgage, supported a family, and built savings while doing my PhD with no issue.
> and then, in your mid-30s, you go on the job market for the first time.
You don't appear on the job market like a newbie. By the time you graduate you should already be well-known enough in your field that you have a reputation, a track-record and several good options. My first job after my PhD was building my own team in industry. It's not like starting a new-grad job.
> Unless you're somehow in the top 0.1% of your field
If you're not in the top 0.1% of your field you shouldn't be doing a PhD in the first place.
> you're probably going to be fighting for a tenure-track positions at any institution that will take you
Why do you assume everyone wants to be in academia? I'm not even sure a majority go into a PhD wanting that. I never did.
> Meanwhile your peers are well established in their careers
Working on a PhD is establishing yourself in your career. But with 1-1 mentorship and a lot of time and space to grow, work with a lot of different people, travel to meet the important people in the field, learn to talk and present your ideas. It's the best way to establish your career that there is.
> have families
You can build a family while doing a PhD just fine. I did. Do you think they bad PhD students from dating or something?
I wasn't even a particularly good PhD student, or at a particularly prestigious institution, and I managed these things.