All other mortals are in a way or another struggling. Pulling all nighters(because it's expected), having long periods of stress + burnout.
The advantages I see are that the money is good and that people(me included) love programming. Having a job doing something you love is definitely a blessing. The biggest of them.
For that I get paid a decent salary for my area, get to do a job I find interesting, and without having to live in London.
That said the average salary isn't worth it at all, but the top end is. You can't really get 6-figures outside of London, but there's plenty of banks that pay that in London.
It's not easy to get a 6 figure GBP salary outside a bank or contracting (usually with a bank), but north of 50K is very doable, and there are a lot opportunities. Rent / mortgage is a low fraction of income especially when your significant other is also making a similar salary (it's about 20% for myself and GF).
I personally like London very much, but eight years of it (and now just a day every two or three weeks) was plenty for me.
My mother had of course never lived in London, just visited once as a tourist. And if you are a tourist you are likely to end up in the busiest, noisiest, smelliest and most expensive parts. But once you live here for a while, and realised how enormous it is, and how many completely different experiences you can have and how many different things you can make of it, there really is something for just about everyone. And now I've settled in a relatively quiet and green area, even my mother is willing to concede that maybe London might have some nice parts.
There are just so many tech jobs available in London. And once you have a job, you have much more flexibility to change jobs without having to move home. This might not be a consideration when you are younger and more flexible in terms of location, but I do know some people who have settled in other parts of the UK who now have families and feel stuck with their current employer due to lack of other opportunities in their area.
And it isn't just the jobs, but also the developer communities. If you live in Shoreditch, for example, you could go to a tech meetup (many with free beer and pizza) within walking distance of home pretty much every night of the week if you really wanted to.
I looked at relocating from London back to Scotland many years ago, and was perfectly reconciled to halving my salary given cost of living and quality of life considerations, but it was simply the relative lack of opportunities that was the main issue in my case.
Of course if you're happy where you are, then stay there. Tis just another option you may not have considered.
Plenty of money to burn in one of the most expensive places in the world for many people probably means just that: A lot of money earned but nothing to show for after years of work.
Compared to that you can make a decent living as an engineer almost anywhere in the world and not blow away all your hard-earned money at the same time.
Then, there are almost certainly Silicon Valley companies where you face stress, burnout and dysfunctional management just as you would in your run-of-the-mill enterprise company that merely treats developers as fungible grunt workers.
The thing that many engineers - perhaps more so outside Silicon Valley - don't seem to get is that they don't have to put up with that kind of abrasive behaviour. That's the most important privilege that comes with this profession nowadays: You basically don't have to struggle to find a way to make a decent amount of money as much as other people do.
If your work environment is a Dilbertesque nightmare you don't have to just endure that until you retire (or drop dead due to stress, whichever happens first ...). Opportunities are a plenty, not just in Silicon Valley but almost everywhere today!