Living in or near London is not a right. Live somewhere cheaper if you cannot afford London. People not in benefits have to make this choice all the time.
Well the media and many people on MN seem to think it is a right for other areas, like Cornwall. The right to be living in your home area - where you're from, where you have family, community, childcare, and a support network.
Talking of childcare, that's gone if a London local moves away. Often family help with childcare is the only way many families can afford to work at all.
Then there's support networks. Particularly vital when someone is vulnerable. Disabled or long term ill, for example...eg. many benefit recipients.
It's not the fault of Londoners that Tony Blair and his successors want to turn London into an exclusive playground for the rich (who then fuck off back to their home town or somewhere in the countryside, after they've made enough money out of London, often at the expense of Londoners).
Btw who does the essential jobs in London if only the rich are allowed to live there? The cost of housing in London is now so high that even roles thought of as well paid, like doctors, are struggling.
It's lucky for London's current mayor, Sadiq Khan, that the Rich Only policy wasn't in place when he was growing up with his bus driver dad.