Not that I want to get into an argument on this (both cities are fantastically expensive), but the first property on your link when I accessed it (so basically at random) - GBP 5590.00 pcm.

the average londoner doesn't pay 5600 GBP a month for their flat. same goes for 5k USD ~= 4200.

for a one bedroom if your rent is above 2000 GBP you're living in a luxury apartment

The average londoner doesn't live in central London.

even within zone 1, the average definitely isn't 4200 GBP