Central Park, Covent Garden, Saint-Germain-des-Pres...). Two, pour in money into your country/city as if it's all an extension of your living room to make your 'area of habitation' match your status and taste. The moderately rich do this with their street/neighbourhood.
This, over time and with enough HNIs in that neighbourhood, is what makes a neighbourhood 'posh'. That's what Amrita Shergill Marg is about. That's what Altamount Road is about.
They didn't turn up as top-end neighbourhoods from the day Delhi and Mumbai were created. Responsibility for a country's upkeep and look — as opposed to intangibles usually bandied about as excuses like 'GDP' — is usually seen as the state's. Well, that's not really a lifetime proposition.
Read more on economictimes.indiatimes.com