You can visit poor countries and still see the same lifestyle. I am from a poor country and there are some areas in my city where people pay hundreds of dollars in fancy restaurants, show up with very expensive cars and etc. You won't believe but in a country with an average 400$ a month salary, almost everyone owns iPhone. But when you visit their houses, you'll be amazed when you see how poor they look inside. Don't be amazed when you see that kind of lifestyle in London but always remember that that's not how everyone lives. Those people have such a good life because other people work very hard to earn money to buy food and feed their families, provide them with basics. You won't see this part of people in a central square with a Ferrarri.
I understand what you mean about poor countries but this is London he’s talking of. I think I didn’t really emphasize enough on how big London is. Imagine that there are places in London where people spend £3,000 to £4,000 a month just for what they call a studio apartment. So imagine a place where luxury exits so much, you shouldn’t be surprised or think otherwise if you see someone who looks wealthy. No one really cares about the iPhone you’re using there because there are wealthier people than those who even rush to buy it.