I don't think Chelsea is remotely representative of "the average London street", and the more representative London street absolutely does have people on below "living wage" renting by the room (or sometimes sharing rooms) on the same street as people owning £1m houses outright.

Fair enough but I think there’s a distinct difference between a well-off home owner and a renter living on the same street vs. a broad mix of social classes all living in basically the same size apartments in the same building. I talk to my building neighbors all the time, but rarely the people in the building across the street.