I followed the links and looked at the various "outrageous" apartments. I had a bedsit in London (near the Heath) which was as small/smaller than the examples shown, with a shared bath in the hall. Instead of a wardrobe, there was a small hanging pole (about 18") over the foot of the twin-sized bed. A sink and a plug-in burner sitting on the little counter, no refrigerator. Small table with a chair. I was in my twenties, working in London, and it was fabulous. I'm still friends with my landlords and have visited them repeatedly (they're now retired and live elsewhere in Britain).
The only deal-breaker I see with any of these is the illegal access for the above-mentioned room: 27 inches high is not safe in an emergency.
Most people in the world live in much smaller spaces than the average U.S. suburban home. That's OK.