A common comment on the eurozone crisis is that it would be very difficult for any country (say Greece) to leave the eurozone. There is even a prize for someone to come up with a good way, which Tim Hartford tells us would be very hard to win.
That the debt problem in itself would not go away by changing currencies is clear. But decolonisation involved literally scores of new countries issuing new currency in replace of the imperial currency. (Not India, it was always on the rupee, but plenty of African countries, for example and including by countries such as Canada, Australia, the US if you go far enough back ....) Why is leaving a currency zone and adopting a new currency regarded as so hard? It has been done many times.
UPDATE. Ed Dolan sets out the mechanisms by which countries have exited from currencies.
Colour films were initially thought to be uncompetitive on cost grounds - People said "what's the point?" about color films https://t.co/1AGXHf7EiB pic.twitter.com/TjhP2dqSmZ — Pessimists Archive (@PessimistsArc) January 10, 2016...
5 minutes ago