The bigger the bubble, the longer the hangover.
But what would happen if they did actually go? As Danny Dorling, the Oxford professor of geography, notes, the ultra-moneyed classes do abandon cities – “at a time of their choosing”. Long Island was once so rich as to be the setting for the Great Gatsby – until the crash of 1929. Now the grand houses remain but the big-money holidays at the Hamptons. (For more data, look at Dorling’s new book A Better Politics, free online here.) The other thing we know is that cities that get too high on speculation face a long, long hangover.
In the late 17th and early 18th century, Amsterdam was as pre-eminent a world city as London is today. The Netherlands was enjoying its golden age of peace with England, and – as Neil Monnery points out in his book Safe As Houses? – the exclusive Herengracht was the Dutch canalside equivalent of Kensington. Then the bubble popped. Using detailed land registers, economic historians can tell us what happened next. House prices peaked in 1738. During the next 20 years, prices fell by a third. Once you adjust for inflation, property prices in Amsterdam would not reach their 1740 levels again for another 250 years.
Could that happen here? The big difference is that wealth is far more footloose than it was in the 18th century, so a similar process could happen in far less time.
The super-rich blackmail us with threats to leave the UK. We should call their bluff