> That makes it sound like a small miracle that 80% of the people there can afford to live there at all.

Oh it absolutely is! People in London pay a lot of money just to be there, and over the last couple of decades I've watched friends move further and further out, some still in flat-share arrangements into their 40s, as the idea of owning property anywhere in anything resembling an inner zone moved from "expensive" to "surely nobody can afford that?" to completely out of the question. And my friends tend to be at least vaguely professional workers, which of course means they are part of waves of gentrification pushing the people with less resources even further away.

How the whole thing sustains itself is something of a mystery to me. The city still needs cleaners.

(FWIW the whole of the UK is pretty much used to quite small living accomodation now, compared to the average American or Australian home)

Kinda seems like it! I was back there for an industry conference a couple days ago actually and a number of the service staff who were around my age (20s-early 30s) actually asked me about how to immigrate to the US and Canada. Tbf this is anecdotal and I'm sure there are other Brits on this forum who can probably give more information.